DEERFIELD BEACH, Fla. -- Police are investigating a disturbing discovery at the Deerfield Beach home of the sister of Michael Brewer, a 15-year-old boy who police said was set on fire by a group of teens.

The act of vandalism happened at the home where Brewer's 22-year-old sister, Melissa Durkee, lives with her children. Someone took two plastic dolls that were left in the front yard, burned them and then threw the charred remains into the back yard pool.

The vandals' actions ostensibly mimic what happened to Brewer. Investigators said that last month, a group of teens doused Brewer with rubbing alcohol at a Deerfield Beach apartment complex and lit him on fire. He jumped in a swimming pool to quench the flames.

Durkee told Broward Sheriff's Office investigators that the dolls belong to her daughters, who had left them in the front yard with other toys the night before.

Detectives said Durkee heard her dogs barking in the middle of the night but did not go outside to investigate. The next day at about 1 p.m., she noticed a gate was open and found the dolls in the pool.

The incident happened as Brewer remains hospitalized, fighting to recover from burns over 65 percent of his body.

BSO investigators went door to door, checking to see if any neighbors saw anything suspicious. No arrests have been made.

Brewer's parents continue to keep a vigil at his hospital bedside. They released a statement Thursday that said, in part:

"The family is sincerely thankful for your concern for our son Michael. However, we are not allowed to comment on an ongoing investigation."