Medically-trained neighbours rushed to Aaron Carter's home in Lancaster, California on Saturday to offer their assistance but were allegedly refused entry by the singer's house sitter.

Couple Anthony and Amanda Cheval said they rushed to the singer's home around 11:00 a.m. to offer medical care when they heard the frantic 911 call on their police scanner. Amanda, 30, a registered nurse, said she brought an automated external defibrillator bag in a bid to save him. But was told by the unnamed house sitter that the singer was already "dead."

"I heard them call out a 927D — code for a possible dead body — for Aaron Carter's address," Anthony, 45, who teaches CPR as part of his job as a corporate safety manager, told the Daily Mail.

He added, "I knocked on the door several times. Finally, after a few minutes, a black female answered the door." Anthony alleged that the woman was "foaming at both sides of her mouth" and kept screaming over and over, "He's gone, he's dead, he's gone."

Anthony pleaded with the woman to let him and his wife in so they could help. But she was "hysterical" and "locked the front door" instead. She told them, "I can't let you in" before she ran away from the door.

Anthony claimed the house sitter also refused to let the L.A. County Sheriff Deputies into Carter's home, alleging that she only opened the door a fraction of the way. But they "pushed past her and ran inside."

He remembered, "Minutes later they exited the house, but not with the same urgent demeanor they had going in. At that point, I thought whoever it was inside there is dead." Anthony said he only realised afterward that Carter was dead when he saw the singer's ex-girlfriend Melanie Martin sobbing on the street.

According to TMZ, the house sitter did not see the singer all day Friday and checked to see if he wanted coffee on Saturday morning. She heard his dog barking in his bedroom and checked to see what was going on. That was when she discovered his dead body in the tub.

A time and cause of death have yet to be revealed. Responding officers allegedly found several cans of compressed air in his bathroom and his bedroom, as well as prescription pill bottles. Officials believe Carter had been dead for a long time as there was reportedly already a smell of decomposition and the water in the tub had turned an unnatural colour.

 Aaron Carter
Aaron Carter attends 102.7 KIIS FM's 2017 Wango Tango at StubHub Center on May 13, 2017 in Carson, California Getty