A fire chief in Massachusetts is investigating why it took nearly 20 minutes for an ambulance to arrive at the scene of a fatal shooting at a baby shower over the weekend.

The first call that 16-year-old Chantel Matiyosus had been shot as she left the shower in Brockton came in at 10:57 p.m. on Saturday.

Although a police cruiser was at the scene in 6 minutes, ambulances did not arrive until 11:14 p.m. and 11:15 p.m.

Fire Chief Kenneth Galligan told The Enterprise of Brockton that there are three ambulances covering the city on weekends and they are often tied up. That appears to have been the situation on Saturday when one ambulance was on a call and two others were at the hospital, he said.

It usually only takes about 6 minutes for an ambulance to get to the scene, according to Galligan.