... The police believe that the three boys, ages 5, 6 and 11, climbed into the trunk while playing on Wednesday night, and that the lid then slammed shut behind them, trapping them inside, said Vincent P. Sarubbi, the prosecutor.
"There were no signs of trauma, no signs of assault," Mr. Sarubbi said. "This was a horrible accident."....
One of the boys - Mr. Sarubbi would not say who - liked to "play with the knobs and switches" in the car, which had been parked in a bed of weeds next to the house for several weeks because it had a brake problem.
The car also had a trunk problem. According to police, the trunk lid would not stay up after it was opened, and instead slammed shut.
The police believe that during the few minutes when the mother took her eyes off the children, the boys scampered into the trunk, and it locked behind them. Either the trunk was ajar or one of the boys pulled the release latch inside the car to open it.
http://www.nytimes.com/2005/06/26/nyregion/26camden.html