Zach Jewell

Three days earlier, officers arrested him on suspicion of driving under the influence, but he was later released for a lack of evidence.

Relatives said they reported him missing after his release, and now they want to know how he got into the vehicle and why he remained there for days unnoticed.

Police Chief Rocky Wenrick said the car, quote, should have been secured, that an independent firm is investigating, and that Valencia's cause of death remains unknown, pending an autopsy by the Los Angeles County Medical Examiner.

Richard Williams.

a grandfather was attacked on March 8th at an Upper East Side station.

After Williams died of his injuries, prosecutors upgraded the charges against the suspect, 34-year-old Byron Hernandez, from assault to second-degree murder.

Police say Hernandez pushed Williams and a 30-year-old man onto the tracks.

Bystanders managed to pull both victims back onto the platform before a train arrived.

While the second victim was hospitalized with non-life-threatening

injuries, Williams hit his head on the tracks, an injury that proved fatal.

The medical examiner has since ruled Williams' death a homicide.

Hernandez fled the scene but was later taken into custody at a homeless shelter.

No motive has yet been given.

DHS says Hernandez is a, quote, serial criminal with a lengthy rap sheet of at least 15 prior charges, including aggravated assault, weapons possession, and domestic violence.

He'd been deported four times after first entering the country illegally in 2008.

The Department of Homeland Security says the suspect was born in Lebanon in 1985 and first entered the United States in 2011 on an immigrant visa as the spouse of a US citizen.

After he applied for naturalization in October 2015, he was granted citizenship in February 2016.

On Thursday, he drove his car into Temple Israel, the largest Reform Judaism congregation in the United States, and opened fire with a rifle.

He was pronounced dead at the scene after the synagogue's security engaged him with gunfire.

One security guard was injured as a result of being struck by the attacker's vehicle, but is in stable condition.