L.A. man pleads not guilty after shooting rampage that killed 4 — including his dad

A Los Angeles man charged with killing four people, including his father, in a shooting rampage has pleaded not guilty to murder.

Gerry Dean Zaragoza also entered pleas to attempted murder and robbery Monday.

WATCH: Jan. 5 — 3 killed, 4 wounded after shooting at L.A. bowling alley

1:30 3 killed, 4 wounded after shooting at L.A. bowling alley

He could face the death penalty if convicted.

Prosecutors say Zaragoza wounded his mother and killed his father and brother in their Canoga Park home on Friday, then killed a woman he knew and wounded another man at a gas station.

Get daily National news

Get the day's top news, political, economic, and current affairs headlines, delivered to your inbox once a day.

Sign up for daily National newsletter Sign Up

By providing your email address, you have read and agree to Global News' Terms and Conditions and Privacy Policy.

READ MORE: Gunman arrested after 12-hour shooting spree kills 4 in California

They say he then tried to rob someone at a Bank of America ATM before shooting a stranger in the head on a bus in Lake Balboa, killing him.

Authorities haven’t identified a motive for the killings.

However, an acquaintance of Zaragoza’s father says the man had confided his 26-year-old son had a drug problem.

WATCH: Oct. 15, 2016 — Three dead, dozen wounded in LA shooting

0:32 Three dead, dozen wounded in LA shooting