A record isn't required, just a loon and a gun.

Vargas, who has no known criminal record, set a combustible liquid on
fire in his fourth-floor apartment. Building manager Italo Pisciotti,
79, and his wife, Camira Pisciotti, 69, saw smoke and ran to the unit,
Zogby said. When they arrived, Vargas opened the door and fired,
killing both.

Detectives were investigating whether Vargas had any ongoing disputes
with the building manager, as some residents believed. His mother was
not home at the time.

After gunning down the building managers, Vargas went back into his
burning apartment and fired 10 to 20 shots from a 9mm pistol into the
street. One of the bullets struck 33-year-old Carlos Javier Gavilanes,
who was parking his car after returning home from work. Zogby said his
body was found next to his vehicle.

The gunman then kicked his way into a third-floor apartment, where he
shot to death Patricio Simono, 54; his wife Merly Niebles, 51; and
their 17-year-old daughter. Family members said Simono worked at a car
wash and Niebles cleaned hotel rooms. Their daughter wanted to be a
nurse.

All six people were killed in a short time span, Zogby said, and it's
possible they were all dead by the time police arrived.