ISSAQUAH — A tense 16-hour standoff between police and a barricaded man ended in a devastating house fire Sunday after SWAT teams rescued four hostages, including two young children, and detectives unsuccessfully tried to negotiate the surrender of the suspect, who is believed to have perished in the flames.

Police tried in vain to convince the suspect to surrender, but rescued the hostages in two separate SWAT team operations, said Washington State Patrol spokesman Chase Van Cleave, during a news briefing posted on KING 5’s Facebook page Sunday night as fire crews searched through the debris of the home in Issaquah’s Montreux neighborhood.

The suspect, who police said was armed with a handgun, was identified as the 28-year-old brother of the woman who lived at the home, located in the 5200 block of Isola Place Northwest.

The woman was at home with her boyfriend and two children, ages 5 and 8, when the suspect forced his way inside at gunpoint shortly before 8 p.m. Saturday, according to Issaquah police. The woman called to report a suspicious person in her yard, but when officers arrived they could not find anyone. Police were trying to contact the homeowner when she called and reported that she and her family were being held at gunpoint.

No identities were released Sunday.

Van Cleave said repeated efforts by police negotiators to contact the suspect over the next five hours were not successful, and just before 1 a.m. a King County sheriff’s SWAT team entered the home and rescued the boyfriend and two children. Van Cleave said the suspect and his sister were in a different part of the house and SWAT was not able to reach her.  He said nobody suffered any physical injuries, but that the situation had been “traumatic” for everyone involved.

Over the next 9 1/2 hours, negotiators continued without luck to try to win the release of the homeowner and convince her brother to surrender, Van Cleave said.  About 10:25 a.m. Sunday, he said a second SWAT operation was able to rescue the sister unharmed, leaving the suspect alone in the house.

Within minutes of the sister’s rescue, SWAT teams deployed gas into the house. Van Cleave said he did not know what kind or whether the type of canisters used was capable of starting a fire. He said fire investigators from King County are involved in the investigation. Again, after the last hostage was rescued, negotiators were unable to raise any response from the home, Van Cleave said.

He said fire investigators were going through the smoldering remains of the badly damaged home Sunday night, but were impeded by unstable conditions. As of Sunday evening, the gunman had not been found.