Boston police are investigating the death of a woman whose body was found in a large nylon bag in an alley in the city's East Boston neighborhood.

A police spokesman on Thursday said investigators were trying to determine the woman's identity, cause of death and how her body ended up in the alley. She appeared to be in her 30s.

Police say officers responding to a 911 call found the body near a Princeton Street home at about 7:20 p.m. Wednesday.

A police dispatcher told the officers that an unidentified caller said that she had seen a suspicious-looking plastic bag, the size of a laundry bag, near the home. The caller also said that the bag appeared to be heavy.