CHULA VISTA (CBS 8/CNS) - An investigation is underway Tuesday into a crash that killed a disabled man and father of two in Chula Vista.

Detectives covered a man's body involved in a hit-and-run accident. His mother says 37-year-old Marcelo Sanchez came back from Jack-in-the Box around 9:30pm Monday.  

Police say he was killed after getting out of his parked car at the 1600 block of Hilltop Drive in Chula Vista near Main Street.

His mother says she heard a loud noise outside of her home. She says Marcelo was knocked unconscious. 

A medical examiner will conduct an autopsy Tuesday. 

At a second scene, police say they found a "black Nissan Frontier pickup truck" with front end damage and a flat tire.

Officers say the possible driver told his family he crashed into a car on Main Street. Police searched the area and found the front logo to a Nissan at the original crash site, which is now part of evidence, officials said.

Police impounded the pickup truck and took it away from the 1600 block of Nacion Avenue. The victim's mother is heartbroken. 

"It's the most heartbreaking thing in the world, it's my son. I pray to God he gives me peace. It's hard for me to take it right now. I just want justice because he killed my son. Eventually he has to know because there was a big bang there and he took off, he killed my son," Martha Sanchez said.

Sanchez was a loving father of a 1-year-old and a 3-year-old. He was going to have back surgery in three days.

The possible driver agreed to a blood test and police say he may have been driving on a suspended license. Authorities said alcohol was not a suspected factor in the crash.

Detectives say he is only being questioned at this time and has been cooperative with police.