WORCESTER - Police investigating the death of an 18-month-old boy remained all day Monday at the Sigel Street apartment where the child lived.

Police were called about 8:45 p.m. Sunday to 20 Sigel St. on a report that a child was not breathing. Police radio reports indicated the mother made the call for help.

A neighbor said he went outside and saw police cars, two ambulances and a firetruck before one of the emergency personnel came quickly from the house carrying a small child in his arms.

"They worked on the baby for a while in the ambulance," the neighbor said, adding that the baby did not appear to be alive. He said he had not seen the child before but that the family lives on the third floor and have been quiet. He said the three-decker is transitional housing and tenants don't usually stay very long.

Sunday night, officers converged on the house, blocking intersections as an ambulance rushed to UMass Memorial Medical Center - University Campus.

A police spokesman confirmed Monday morning the child died and that an investigation is ongoing.

Kim Ring of the Telegram & Gazette staff contributed to this report.