Man kills ex-girlfriend, wounds clerk in Antioch store, police say

Thomas John Williams Jr. was booked on suspicion of murder and attempted murder Monday after a double shooting in Antioch killed his former girlfriend and wounded a convenience store clerk. Thomas John Williams Jr. was booked on suspicion of murder and attempted murder Monday after a double shooting in Antioch killed his former girlfriend and wounded a convenience store clerk. Image 1 of / 1 Caption Close Man kills ex-girlfriend, wounds clerk in Antioch store, police say 1 / 1 Back to Gallery

A man fatally shot his former girlfriend in a liquor store and badly injured a clerk who tried to intervene Monday morning in Antioch, police said.

Officials said the suspect, 34-year-old Thomas John Williams Jr. of Oakland, got into an argument with the victim, 27-year-old Cynthia Flores-Crose of Antioch, outside the Quik Stop on the 2700 block of West Tregallas Road near Lone Tree Way about 7 a.m.

Williams followed Flores-Crose into the store, where he began shooting, police said.

The store clerk, Thomas Payne, a 27-year-old Antioch resident, tried to help but was wounded by the gunfire, police said. He was rushed to a nearby hospital and is expected to survive.

Later in the morning, Williams showed up at the Antioch police station, where he was arrested. Police booked him at the Martinez Detention Facility on suspicion of murder and attempted murder.

Kimberly Veklerov is a San Francisco Chronicle staff writer. Email: kveklerov@sfchronicle.com Twitter: @kveklerov