ARLINGTON, Texas - A rookie police officer was fatally shot as she apparently tried to protect an 11-year-old from an armed man who burst into an apartment as the officer was taking a domestic-assault report, police officials said yesterday.

Jillian Michelle Smith, 24, was killed Tuesday night within 20 minutes of responding to a lower priority call from a woman who wanted to report the assault, officials said.

The assault suspect had left the apartment but returned while Smith was inside taking the report, Arlington police spokeswoman Tiara Ellis Richard said at a news conference yesterday.

Also killed were Kimberly Deshay Carter, 29, and her ex-boyfriend, Barnes Samuel Nettles, 38.

After shooting Smith, Nettles apparently went into a back bedroom and shot Carter, Richard said.

He then returned to the living room and shot himself, Richard said. In the meantime, the child, identified as Carter's daughter, fled.

Richard said that the description of what likely happened inside the apartment was based on a preliminary investigation and that the order of events would be pinned down more specifically after reports by the medical examiner, ballistics and other information.

In Mobile, Ala., Nettles' relatives called the shooting a selfish act and said that they didn't realize that Nettles and Carter were still in contact.

"We are at a loss right now," said Nettles' cousin Andrew Johnson. "We're just sorry for the relatives of both victims. It was selfish."

In September, Nettles was arrested in Arlington and charged with assaulting Carter's mother and sister, Richard said. Court documents show that he was free on $5,000 bond.

He was a registered sex offender in Arlington for an offense that occurred in Washington state, Richard said.

Smith joined the department in February and graduated from the Arlington Police Academy in August. She completed her field training Dec. 13, said Richard, the police spokeswoman.

Officials said that it is not unusual for a lone officer to respond to a Priority 3 call.

The incident began when Smith responded to a call about a domestic assault at the Arbrook Park apartment complex, Richard said.

Within 20 minutes, police received a 9-1-1 call about a shooting.

"When they responded, they discovered there were three deceased inside the apartment," Richard said. "One of these was the officer who had responded earlier."

Officers could be seen searching people and cars as they left the complex in the pouring rain late Tuesday.

Yesterday, two neighbors at the apartment complex said that they were stunned not only by the violence, but by the fact that they never heard gunshots.

According to court documents, local defense attorney Abe Factor was appointed to represent Nettles in September after he indicated that he could not afford a lawyer.

Nettles stated in court documents that he was an unemployed sheet metal worker, who was supporting himself and three sons, ages 18, 14 and 11.

He listed his gross monthly income as $1,340 from "odd jobs," and stated that he also received food stamps and Medicaid and had filed for child support."