SULTAN, Wash. - Two more people have been arrested in connection with the stabbing death of a teen on Wednesday, and officials said the 17-year-old victim died from knife wounds to the torso and blunt force injury to the head.

The latest arrests - of a 16-year-old boy and a 16-year-old girl - bring the total number of arrests in the case to five, said Snohomish County sheriff's spokesperson Rebecca Hover. All five suspects are being held for investigation of second-degree murder.

The Snohomish County Medical Examiner identified the victim Thursday as Antonio Faris Marks, 17, of Marysville. Authorities initially thought he was a 15-year-old from Lynnwood.

The fatal injuries included a sharp force injury to the trunk and a blunt force injury to the head, the Medical Examiner's Office said.

Police earlier arrested two brothers - a 19-year-old man and a 16-year-old boy - as well as a 17-year-old girl in connection with the killing of a 15-year-old boy. All three are from Sultan.

Hover said the two brothers live at the house in the 200 block of Cedar Street where detectives served a search warrant late Wednesday. The girl is not related to the brothers, she said.

Police searched the brothers' home on Wednesday, just hours after the victim was found lying in the street nearby, at the intersection of 4th Street and Main Street.

"We saw the (victim) shaking his head," said witness Krystal Chaffee. "It looked like he was in and out of convulsions."

The boy was taken to Harborview Medical Center in Seattle to be treated for several stab wounds to the stomach, but he was pronounced dead when he arrived.

Officials are reviewing footage from video surveillance cameras near the scene of the stabbing for further evidence.

Neighbors said the home that police searched was the scene of a loud party in the hours before the stabbing. They reported the party to authorities, but said it broke up just after midnight - minutes before the victim was found.

Neighbors said the family who lives at the home has five children, four of whom are teenagers. They said the two oldest boys are known to be troublemakers.

"These guys started moving in a year and half, two years ago," said resident Caleb Blankenbaker. "They started acting like there were gangs around here, and everybody started grouping together."

Lt. Jeff Brand said the victim apparently knew the attackers. A motive has not been established.