. >> mrs. cullin was one of the nicest ladies i ever enun the whole thing is a tragedy. >> reporter: two family friends say cullin jr had a long history of mental illness. when he stopped taking his medication, prosecutors say, his mom confronted him on wednesday, prompting the alleged attack. >> he put her in a head lock, walked from the shallow end of the pool with her in a head lock to the deep end all the time while she was struggling. >> reporter: the prosecutor says that water struggle was violent. surprised him because his mom was only about 5'2". he dumped her body by a shed. >> he hasn't been convicted of anything. he hasn't said "i'm sorry." >> cullin jr's lawyer entered a not guilty plea for the young man who lived with his parents on this sprawling property. neither his father or three sisters appeared with him in court. >> this is a son who killed his mother and the way he killed her, was done is chilling. >> reporter: cullin jr was ordered held on $8 million bond. his mom was an interior

. >> mrs. cullin was one of the nicest ladies i ever enun the whole thing is a tragedy. >> reporter: two family friends say cullin jr had a long history of mental illness. when he stopped taking his medication, prosecutors say, his mom confronted him on wednesday, prompting the alleged attack. >> he put her in a head lock, walked from the shallow end of the pool with her in a head lock to the deep end all the time while she was struggling. >> reporter: the prosecutor says that water struggle was violent.