in september 2014, 43 students disappeared from passenger buses in the mexican town of iguala, guerrero. they were in police custody, and then they're just gone. the federal government took charge of the case. police started finding many places with clandestine graves. it was just horrifying. just three months after the disappearance, the government announced they had solved the case.

we were analysing the evidence. it was just not matching the official story. protests erupted across mexico. a team of independent experts began their own investigation and the government case starts to unravel.

the mexican government claimed the students were on four buses when they were attacked. but cctv revealed students on a fifth bus.

we saw that the mexican government was officially stating that the guerreros unidos were simply a local gang, and we knew that not to be the truth at all.

my name is mark guiffre, and for 30 years, i was a special agent with the us drug enforcement administration. prior to the disappearance of the students, we had received intelligence that there was going to be activity relating to the movement of illicit heroin proceeds coming out of this particular location. we got authorisation to conduct a search of that location. and there we seized many kilograms of heroin, money counters, a quarter of a million dollars or so in cash and illicit heroin trafficking records. we knew that day that we had cracked into a major criminal organisation with direct ties

to iguala, guerrero. we received orders from a us district courtjudge and we began to conduct intercepts. we initiated surveillance operations, and in a very short period of time, we were able to determine that they were using passenger buses to smuggle large amounts of heroin — in hidden compartments — going back and forth between the chicago area and guerrero, mexico. based on the intelligence, we could easily determine that this organisation, conservatively, was smuggling 200kg a month to chicago, which is over 2,000 kilograms a year, which is an absolutely unprecedented amount of heroin coming in to the united states by a single organisation. that's well over $122 million in a year.

it was mind—boggling. what mexican authorities were saying was that nobody knows for sure why the students were attacked and disappeared. we knew that buses were being used by the guerreros unidos cartel. and we knew that the students were on buses. it seemed to us that it was clear as could be that the students unknowingly hijacked the wrong bus.

four years on, the remains ofjust one student have been found. there have been a handful of arrests, but no convictions.

and the parents are still searching for their missing sons.

viva mexico! in 2018, there's a presidential election. andres manuel lopez 0brador was an outsider, a political outsider. he has mass popular support, but the political elite hate him. he won that election with an overwhelming mandate. he made one explicit campaign promise to address an issue of human rights, and that was the forced disappearance of the 43 students. and he did that when he was on a campaign stop in iguala.

he explicitly said, "i will find the 43 students "and i will bring the people who did it to justice." and the families believed it.

when lopez 0brador took power, he issued a decree to set up a truth commission. also, the decree set up a special prosecutor's office. they named the special

prosecutor, 0mar gomez trejo. 0mar gomez trejo was someone with a serious human rights background, a mexican man. he had worked for the independent experts group, the giei. this is somebody who can and will actually investigate.

the previous administration's case had rested on the confessions of cartel suspects.

0mar gomez and his team obtain and verify more than 60 interrogation videos.

by march 2020, there is enough

evidence to indict tomas zeron. he once led the federal investigation into the missing 43. he is now wanted for his alleged role in a cover—up. the mexican government requests an international arrest warrant through interpol. but mexico doesn't have

an extradition treaty with israel.

in the final months of 2019, after discovering the use of torture in the original investigation, key suspects are released from prison and agree to be reinterviewed by 0mar.

the work was for weeks and even maybe some months and, you know, really searching a very large area. and...that�*s where the remains were found. we did the laboratory analysis, the anthropological examination of the remains. and then we analysed the results that came out from the processing of those remains and the identifications that it produced of two more students. the two identifications — one belonged to jhosivani guerrero de la cruz and the other one matched the family of christian rodriguez telumbre.

chanting when the special prosecutor's unit was getting really close to full documentation of the events that night, which included military participation, they dynamited the case.

hello there. a wide range of temperatures on thursday with mild air towards the south, much colder feeling air further north. there was some snow, particularly over the peak district and over the pennines too — here's hebden bridge in west yorkshire. most of the snow came over the high ground. but misty, mild conditions further south. plenty of heavy rain, too. you can see that on the radar picturejust piling into the south of england and south wales earlier on through the night. lots of flood alerts in place here. there's the snowfall further north, most of it over the higher ground, but some of the snow towards the south just turning back to sleet and then to rain with that milder feeling air. but still the risk of some travel disruption as we head into friday with an ice risk from northern england northwards and still some falling snow over the very highest peaks as well. the snow riskjust transferring into central southern areas of scotland, too, and some brisk easterly winds. so perhaps some more

problems over the higher routes in particular with drifting snow. this is how we're starting off the day on friday. a range of temperatures — below freezing in scotland, but very mild in the south. now as we head through friday, that warm front continues to push its way further northwards, just dragging in the milderfeeling air. still very brisk easterly winds blowing across eastern scotland, northeast england. this should be falling as rain. but across the grampians and the highlands, we're likely to see some accumulations of snow, even to low levels from the central belt northwards, but it will turn back to rain. some early wintriness too perhaps across northern ireland. once more, quite a wide range of temperatures — between 4 and 13 degrees celsius as we go through the afternoon, and still maybe a bit of wintriness, particularly across caithness and sutherland and across shetland as we head through saturday. now, there will be a lot of dry weather on saturday, but low pressure is close by and there will be some showers, maybe some heavier rainfall across the far south—east of england a little later on through the day. but coming back up into that milderfeeling air, so most of our temperatures will be between 6

and 11 degrees celsius. still double figures in the south. watch out for some heavy rain again across northeastern areas of scotland as we head through sunday. but it will be falling as rain. the air now a lot milder, some scattered showers elsewhere, along with some spells of brightness. and by the time we get to the end of the weekend, those winds, brisk in the north, will have eased down somewhat, maybe turning more settled into the start of next week with high pressure building in.

live from washington. this is bbc news. in a surprise white house address, presidentjoe biden

responds to the findings of a special counsel investigation into his handling of classified documents. i was pleased he reached a firm conclusion that a firm conclusion that no charges should be brought against me in this case. the us supreme court hears a case on whether colorado can block donald trump from the ballot in the 2024 presidential election in the state. vote counting gets under way in a turbulent general election in pakistan. i'm helena humphrey, good to have you with us. we begin in washington. us presidentjoe biden has defended not only his handling of classified documents at the centre of the justice department investigation but also his fitness for the job leading the country. earlier the day, the person leading the investigation into his handling of documents said, he wilfully