VALLEJO, Calif. (KGO) -- Police are searching for a second man in connection with the killing of a young woman and her unborn baby in San Pablo.
They say they want to talk to Luciano Duarte, calling him a person of interest in the case.
Homicide suspect Luis Monje-Morales Junior was taken into custody overnight.
RELATED: San Pablo police investigating fatal shooting of pregnant woman
Police say they found the 21-year-old hiding in an apartment in Vallejo. He was arrested after a standoff with police.
Investigators don't know the relationship between Morales and the victim, Ilayshia McCoy, but say the two may have dated.
Police say the 18-year-old woman was shot Monday night at the corner of 17th Street and Sutter Avenue in San Pablo.
A friend says McCoy was seven months pregnant.
1 arrested, person of interest wanted in killing of pregnant woman in San Pablo