♪ you don't know me ♪ and i don't know you this is "nightline" -- >> tonight, after two uniformed police officers are gunned down in broad daylight, a city and nation come together in grief, but remain divided on some of the questions raised by the braisen killers. tonight, what was behind the attack and how police are responding. plus, she's the mystery lady of pop. you might not recognize one of the world's most popular singers, and that's just the way sia wants it. she's behind top charters b beyonce and rihanna. but she plays by her own rules. how she battled back from addiction to chart number one hits. ♪ and to some, maria is just a quiet talker.

to others, she's the internet whisperer. >> thank you. >> her voice so calming, she says she can use it to soothe them. >> soft voices. >> lull them to sleep, even cure them on depression. >> it puts you in this e euphoric -- >> but first, the "nightline" five. >> when heartburn comes creeping up on you, fight back with relief so smooth, it's fast. tums smoothies starts dissolving the instant it touches your tongue. only from tums. inside every ricola drop, there's a magic herb blend. for powerful cough relief with a liquid center that calms your cough. ricola extra strength. ♪ ricola

good evening. new york city's mayor is asking for help keeping the peace tonight in the backlash after two nypd officers were shot dead while sitting in their patrol car. their attacker reportedly claimed he was getting pay back for the lives of eric garner and mike brown. now, as our nation continues to wrestle with race and justice, one grieving city tries to heal. a violent ambush. followed by a political firestorm. >> that's blood on the hands and it starts on the steps of city hall in the office of the mayor. >> reporter: tonight, so many mourn the loss of two of new york city's finest, at the hands of a man vowing to avenge the recent deaths of two unarmed black men, eric garner and michael brown, whose killings by police officers sparked nationwide anti-police protests. >> the assassination of these two officers was an attack on

the city of new york as a whole, on every one of us, on our values, on our democracy. >> reporter: it was an attack in broad daylight. the officers shot dead saturday at point-blank range. >> shots fired. >> reporter: their attacker has been identified at 28-year-old ismaaiyl brinsley, a new york native, who police and family say had a history of mental illness and at least 19 prior arrests. authorities believe brinsley's rampage began in the early hours saturday morning, in baltimore, when he allegedly shot his former girlfriend in the stomach inside her own home. he then boarded a bus from baltimore to new york, arriving at 10:50 a.m. seen here in surveillance video, his gun, shorts believe, to be inside that bag. at about 1:30 p.m., he posts a warning on instagram, quote, i'm putting wings on pigs today. they take one of ours, let's take two of theirs. he added hash tacks, shoot the police, plus the names of mike brown and eric garner.

baltimore police alert the nypd, faxing over this mug shot, only two minutes before brinsley opened fire. according to the nypd, the officers were on their lunch break when brinsley walked up to the passenger side of their patrol car and fired four shots. >> shots fired. shots fired. >> reporter: police swarm the scene. rushing the officers to an ambulance, as s.w.a.t. teams chase a fleeing brinsley to a nearby subway station. >> get on the floor. >> reporter: still armed with a semiautomatic handgun, where officials say brinsley shot himself in the head. >> one person is shot. >> reporter: all three men were pronounced dead. yet a curious choice of victims here. brinsley cited the michael brown and eric garner dixes as his motivation for the killings. both cases that focus on a white cop, a black victim. but the police officers brinsley kills, one asian-american, one hispanic. >> he didn't even know who was in that car.

>> reporter: as former police commissioner, abc contributor ray kelly knows very well the dangers officer face. >> it was about blue? >> i think it was just because they were wearing a uniform, they were targeted. >> reporter: today, new york mayor bill de blasio and police commissioner bill bratton visited the homes of both families, both reeling from shock just day bfrs christmas. on facebook, one of officer ramos' sons posted this, "today, i had to say bye to my father. he was the best father i could ask for. it's horrible that someone gets shot dead just for being a police officer." officer liu's widow spoke tonight. >> this is a difficult time for both of our families. but we will stand together and get through this together. >> reporter: since the attack, officers in new york and surrounding cities have been pleased on alert. >> since the incident, we've received a number of what i

would describe as copy cat types of threats. >> reporter: many mourners have visited the fallen officer's makeshift memorials to pay their respects. notably among them, eric garner's daughter emerald, who today, made it clear her family wants nothing to do with violence against police. >> i just had to come out and let the family know that we stand with them and i want to send my prayers and my condolences to the families who are suffering. >> reporter: her own family's tragedy ignited a cry of outrage after a grand jury exonerated the police officers who killed her father. >> feel conflicted at all, given they are nypd officers? >> i don't feel conflicted. it was never anti-police. >> reporter: in the wake of the demonstrations that took over city streets, nypd leaders feel the mayor was too sympathetic towards the anti-police protesters. saturday, when the mayor visited the hospital to pay his respects to the fallen officers' families, a group of police officers turned their backs on him in protest.

>> the experience of this man in terms of some cops not liking him, is nothing new. it's part of life. it's part of politics. >> reporter: bill bratton fully supports the mayor as they work together to investigate this crime. at this point, they believe brinlsley acted alone. police say he was a troubled man isolated from friends and family. he was prone to angry rants against the government on social media. and appears to have latched onto an extreme anti-police cause. >> the focus is on the police because of what they represent. they represent society, they represent law and order. and to be quiet blunt, they are just easy targets, because they're in uniform, in a marked car, and they're everywhere. >> reporter: new statistics of police death show that compared to last year, officers killed in the line of duty have surged by 23%. but those killed by firearms up a staggering 58%. saturday's shooting stands out for a critical reason. >> advance majority of officers

losing their lives are losing it in direct confrontation. but what happened on saturday, i mean, these officers had absolutely no chance, no awareness. it is significant. >> reporter: candles are burns bright as the city mourns two of those sworn to protect and serve, who became victims of a senseless crime. >> in this tragedy, maybe we find some way of moving forward. that it would be an appropriate way to honor these fallen officers and their families that are in pain right now. somehow knit our city together. next, a revealing conversation with the mysterious celebrity, sia. chef uses a mini me in her music video. just one of the ways she stays under the radar. the holiday season is here, which means it's time for the volkswagen sign-then-drive event. for practically just your signature, you could drive home for the holidays in a german-engineered volkswagen.

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her name is sia. she's the anti-celebrity celebrity. she's worked with the biggest names as a song writer, and yet, when it comes to her own hits, her choices are, shall we say, unconventional. she doesn't even show her own face. so, tonight, we're exploring fame with a star who actually has written an anti-fame manifesto. here's abc's chris connelly. >> reporter: this incredible voice has soared to the top of the pop charts. the voice of 39-year-old sia furler. sia, as she is known, has chosen not to show her face on camera when she performs live. or speaks to the media. >> you don't really do entertainment stories, really,

that much, right? >> reporter: not like this, i don't. what makes this the right decision for you to turn your back away from the camera? >> well, i don't want to be famous. or recognizable. i don't want to be critiqued about the way that i look on the internet. i was at target the other day buying a hose and nobody recognized me and my song was on the radio and i thought, okay, this experiment is working. >> reporter: with the video featuring this gifted young dancer, sia's hit single helped her album enter the charts at number one. in what way was it different from what else we were hearing on the radio? >> i guess because it has a dark undertone. sad, right? >> reporter: she's earned four grmmy nominations and a golden globe for her nod for her song from "annie," "opportunity."

♪ standing right in front of me ♪ >> reporter: but sia has been face to face with full-on celebrity. it's not for her. >> i've been writing pop songs for pop stars for a couple of years and have become friends with them and see what their life is like. and it's -- that's just not something i want. >> reporter: kyes, that. sia's become one of pop's most successful song writers. her resume is a who's huge of music superstars. ♪ we're beautiful ♪ like diamonds in the sky >> reporter: rihanna's "diamo "diamonds." flo-rye day's "wild ones." and david guetta's "tie tame one." how long did it take you to write that? >> 40 minutes, maybe, and half an hour to record the vocals. ♪ >> reporter: that's amazing.

what gets you started on a lyric? >> well, i usually choose one solid concept. i see a chandelier. then i'm like, okay, how can i use that? that's a strong title. >> reporter: times her songs pass through more than one artist's hands. take the song "pretty hurt." >> i wrote it on the sofa three years ago for katy perry. i sent it to her. then i sent it to probably rihanna and beyonce's people and beyonce just slid it into home base and threw the money down. it was an awkward situation. ♪ so, rihanna's engineer had a great idea, he was like, why don't you play her "diamonds?" rihanna was like, this is mine. ♪ like diamonds in the sky >> reporter: everybody goes home happy. >> yeah, that's how we like it here at chez sia. >> reporter: why step out and become a artist again? >> i didn't think this music would get hurt otherwise. >> reporter: in 2005, her song "breathe me" was used in the

finale of "six feet under." ♪ i have lost myself again >> i was extreme limb ly depres the time. >> reporter: it wasn't just alcohol for you, was it? >> oh, no. i don't think i ever would have stopped drinking had i not got hooked on zantac and oxycontin. >> reporter: she holed up in her home in 2010, contemplating suicide. she found her way to a 12-step program. was like, oh, my god, this is what was wrong with me all along. >> reporter: so that we might see her creative process at work, sia took us downstairs for a session with slcollaborator chris spray. as we watched and listen, sia began to fashion a pop melody, right there on the stop. ♪

>> so, that's all we would do. can we have a copy of that? nice work. and then have, like, rihanna cut it next week. >> reporter: how much do you tweak the words after you write them? >> i don't tweak them at all. i can make any word fit. ♪ i want to live like tomorrow doesn't exist ♪ like command leer and exist. if you bend them in certain ways. >> reporter: a hook, a distinctive word, the repetition of a strong concept. it's how these two came up with britney's hit "perfume." >> i don't even know if i know the words. we write these songs in, like, 40 minutes and then we just send them to somebody and then we never really refer back to them ever again. >> reporter: pass through your life in an afternoon. >> yes. ♪ is there still a longing th e there ♪

♪ live just you and me ♪ sometimes it feels like there's three of us ♪ ♪ in here baby i just lift these concepts off, like, crap television. and then, like, it's so fun, and i apply them to music. >> reporter: that's why we love this pop muse you can, though, isn't it? >> yeah, because it gets -- there's a story or it makes us feel good or it makes us feel sad. >> reporter: but the odds of the public of the getting to listen to sia in concert aren't good. touring is just not on her menu. >> i mean, i did imagine it, but i've unimagined it. it may change, but right now, that's not on the cards for me. >> reporter: she has performed on "the ellen degeneres show" and "jimmy kimmel live," with her back to the audience. and dance moms star, 12-year-old

maddie zeigler in a blond wig, which sia notes is part of the concept. >> the concept of creating a brand, which is an inanimate object. you can put anyone under it. a man, a woman, a dog. and then everyone can be the singer. >> very happy person. she's very awesome. like, very caring for everybody. we did "jimmy kimmel live," she didn't face the front, she wanted to have face paint. >> reporter: years ago, when sia was maddie's age, colin hay from men at work introduced her to stevie wonder. >> he said, i hope you're happy and successful in everything you do. >> reporter: are you? >> yeah. >> reporter: can you believe it? >> i -- i do have -- i do spend a lot of time, like, pinching myself. i have to say, it's been pretty amazing. i might cry. it's been really amazing. the last couple of years have just been, since i made the decision to just take care of my

own sanity and serenity and stuff, my life has just improved so much. and i'm honestly surprised that things are working out so well for me. >> reporter: i'm chris connell little for "nightline" in los angeles. next -- >> i'm going to -- >> we're finding out about the power of a whisper from an online sensation. listen up. of this year's superstar... (coughs) coughing can really be disruptive. with a record breaking fifty million votes, your superstar is... that's why there's delsym. delsym helps silence coughs for a full 12 hours with an advanced time release formula for all day or all night relief. up to twice as long as other cough liquids. so the only sounds you'll hear are the ones you want to hear. bianca! (cheering)

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♪ that's how it goes whenever it snows. ♪ ♪ the world is your snowball just for a song. ♪ ♪ get out and move it along. ♪

you're about to meet a star who uses youtube videos to make a name for herself. a very, very quiet name. when she whispers to her fans, they say her voice cures all kinds of problems or simply makes them happy. could it help you, too? here's abc's bazi kanani. >> this is marie again with you. >> reporter: she's become a youtube sensation. >> so soft. >> reporter: by making her viewers feel a unique sensation. >> and i'm going to gently whisper into your ear. >> reporter: her fans hanging on her every whispered word. millions watching her fold towels. >> press. >> reporter: massage her face. even play doctor. >> let me listen to your heart. >> reporter: a whisper feels very intimate. >> it does. almost like you are apart of something secret. >> reporter: what is her secret? >> it's a wonderful wave

sensation that travels from the back of your head into your neck. >> reporter: she's describing a condition called asmr. for maria and others who say they are asmr sensitive, certain sounds trigger sublime sensations. >> just tapping. like bubbling in your head. >> reporter: these videos bring her viewers into an intimate experience. watch as she brushes the lens and microphone, pretending to be a makeup artist. >> i'm really trying to break the barriers of the camera and really almost be with them there. >> reporter: science has yet to prove if the asmr phenomenon is fact or fiction. >> tingling sensation is e euphor euphoric. >> for people who have experienced it, they claim some pretty powerful results, but again this is untested. it's unvalidated. and it's really largely unresearched. >> reporter: but maria says videos like these helped her

destress and even overcome depression. >> i want you to remember that you are never alone. >> reporter: proving that a quiet voice can pack a powerful punch. for "nightline" -- >> reporter: bazi kanani, abc news, washington. very soft. >> very soft. >> we'll call her the people whisperer. thank you for watching abc news. "world news now" is coming up soon with overnight breaking news. tune into "good morning america" tomorrow, and, as as or a helping paw!ater, everyone needs a helping hand, so mattress discounters good deed dogs is raising money to help train assistance dogs for wounded veterans.

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