RICHMOND (CBS SF) -- Police in Richmond beefed up patrols over the weekend after a string of shootings left one man dead and another four wounded, a police lieutenant said Tuesday.

Lt. Bisa French said police continue to search for suspects in the shootings that took place on Friday and Saturday, but have yet to determine whether the crimes are gang-related.

The series of shootings began around 8:25 p.m. Friday, when 20-year-old Richmond resident Marquis Hamilton was shot outside of a store near Fifth Street and Market Avenue in North Richmond.

He was taken to Doctors Medical Center in San Pablo where he was later pronounced dead, according to the sheriff's office.

Shortly afterward, a 50-year-old man was shot in South Richmond but was not critically injured, police said.

French said the same suspect vehicle, a black car found abandoned after the second attack, has been linked to both Friday night shootings.

A Saturday evening shooting on Harbour Way left three more Richmond men wounded, the lieutenant said.

French said the shooters fired 27 shots at the three men, who were treated at a nearby hospital.

As of Tuesday afternoon, police had yet to track down a suspect or determine a motive for the attacks.

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