An 8-year-old Tacoma boy called 911 early Wednesday to report his mother was being beaten by her boyfriend, Tacoma police said.
The boy told a 911 dispatcher that the boyfriend was throwing his mother, who was pregnant, to the ground. He said the man had been drinking all night and might own a gun.
Officers arrived in the 900 block of North Pearl Street about 1 a.m. The boy came outside and the officers could see the mother and boyfriend fighting, police said.
The man was subdued and arrested on suspicion of aggravated domestic violence assault.
Medical aid was called to treat the woman, who was five months pregnant, for non-life-threatening injuries.
Police said the woman told them she had been choked to the point of unconsciousness.