The Navy veteran suspected of driving his car into pedestrians in New York reportedly told police he had been hearing voices at the time.
Richard Rojas, 26, is accused of steering his car onto the pavement in the heart of Times Square , driving for three blocks and hitting 23 pedestrians along the way. One of them - a teenager - died.
He then walked from the vehicle waving his arms before being tackled by members of the public, including a ticket seller and a security guard at a Planet Hollywood restaurant.
Initially, there were fears the incident had been a terrorist attack but investigators discounted that and are focusing on Rojas's sobriety and mental health.
Rojas, who lived in the Bronx, said he was hearing voices and had expected to die, according to law enforcement officials quoted by the Associated Press.
He tested negative for alcohol but it is understood that he is also undergoing tests while in police custody to see if he had taken drugs.
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People who lived near Rojas described him as a friendly man who had been having problems.
Last week, he was arrested and charged after allegedly threatening a notary with a knife. He had accused the notary of stealing his identity.
In 2008 and 2015, he was arrested for drink-driving. After pleading guilty in 2015, he lost his driving license for 90 days.
During this time, he had told police he was being harassed and followed.
Rojas enlisted in the US Navy in 2011 and served on the destroyer USS Carney in 2012.
His most recent base was at Jacksonville in Florida but he was discharged three years ago after being court-martialled for reasons that have not been disclosed.