SAN DIEGO (CNS) - Two preschoolers are orphans Thursday following the violent deaths of their parents, both of whom served in the Navy, in a presumed murder-suicide at the family's home in a Serra Mesa military-housing complex.

One of the children, an 18-month-old boy, was in the residence in the 3300 block of Wainright Lane when Sekai and Portia Southern died of gunshot wounds on Wednesday afternoon, according to San Diego police.

Investigator believe that Sekai Southern, a 36-year-old military instructor, gunned down his 26-year-old wife before killing himself with the same gun, homicide Lt. Ernie Herbert told reporters.

A neighbor had made an emergency call about 12:30 p.m. to report a disturbance at the Southerns' home, Herbert said.

Arriving patrol officers saw Sekai Southern pulling his wife into the residence through the front door as she apparently was trying to flee to safety. The serviceman refused repeated entreaties to set the woman free and surrender, prompting officers to evacuate nearby houses and call in a SWAT team.

Shortly after 3:30 p.m., the special weapons and tactics personnel entered the couple's home and found them dead, the lieutenant said.

The toddler was in a playpen, unhurt. His 5-year-old sister had been at a day-care center during the standoff, according to police, who said the motive for the violence was unclear.