LONG BEACH (CBS) — Police conducted a homicide investigation Wednesday after finding a woman dead inside a home in Long Beach.

The body was found around 4 a.m. inside a ground-floor unit of a triplex in the 100 block of Ellis Street, near Long Beach Boulevard, according to Lt. Paul LeBaron of the Long Beach Police Department.

"We have made entry into the residence. We have determined that it is a homicide. The victim is an adult female," LeBaron said.

(UPDATE: Wednesday 4 p.m.) Police announced the arrest of a 49-year-old man, described as the victim's boyfriend, as a suspect in the homicide.

An anonymous caller phoned police around 6:15 p.m. Tuesday asking them to make a welfare check at the residence, but police did not enter the premises until they secured a search warrant, he said.

The cause of death remained under investigation.

Police have withheld the woman's name and cause of death. The victim was believed to be 51.

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