JANESVILLE, Wis. -- A 4-year-old boy accidentally started a fire that killed his 7-year-old brother and injured his 2-year-old sibling in Janesville, Wis., during the weekend, according to authorities.

Derek Mattingly, 7, was killed in the fire that broke out on Saturday morning on North Palm Street on the city's northwest side. His 2-year-old brother was flown to a Milwaukee hospital. He's recovering and currently listed in improved condition, Madison station WISC reported.

Officials said that the boys' father, the 4-year-old and the boys' grandmother escaped.

Janesville fire officials said that the boy who started the blaze alerted his father, but he was unable to evacuate all the children.

The Fire Department is issuing a citation to the building's owner for not providing enough smoke detectors in the apartment.

Sheila Miller, a neighbor of the family, has put together a fund to help the family following the fire. Those wanting to contribute should send their money to: Mattingly/Ashmore Family Benefit Fund
Anchor Bank
P.O. Box 8070
Janesville, WI 53547

Donations can also be dropped off at any Anchor Bank.

A candlelight vigil will be held in front of the house on Monday night.