PICTURED: Adorable six-month-old baby who baked to death in Arizona after being 'forgotten' in hot car for SEVEN hours - as teenage neighbor is arrested

A baby has died in a hot car after a teenage neighbor allegedly forgot to drop him off at his father's house and he spent seven hours locked inside.

Travis Carter Jr was found unresponsive in the back seat outside the neighbor's house in Cordes Lakes, about 60 miles north of Phoenix, Arizona.

Paramedics pronounced him dead when they arrived about 9pm on Tuesday. The juvenile neighbor was later arrested and charged with negligent homicide.

The six-month-old boy's mother Aleesia Phillips earlier that day enlisted the neighbor's help to drive her to Prescott Valley, police said.

Travis Carter Jr was found unresponsive in the back seat outside the neighbor's house in Cordes Lakes, about 60 miles north of Phoenix, Arizona

The neighbor was supposed to take the boy to his father Travis Carter (right) when his mother Aleesia Phillips (left) went to work

Phillips took Travis along with her in the back seat, and after he fell asleep she asked the neighbor to drop off the baby at his father's house when she went to work.

The neighbor arrived home, next door to the boy's father, Travis Carter, about 2pm, but did not take them inside.

Instead, they 'parked the car exposed in the hot sun and went into their house, claiming to forget about the baby in the car', police alleged.

Carter called Phillips, who was still at work, about 8.45pm to ask what time the neighbor would be dropping off Travis.

She immediately called the neighbor to find out what was going on, and only then did they realize the baby was still in the car.

'The neighbor ran next door to the father's house and both the father and neighbor pulled the baby out of the car, called 911 and tried CPR,' police said. 

The Yavapai County Sheriff's Office began investigating and on Thursday arrested the neighbor and charged them with negligent homicide. 

Phillips (pictured with her older child) asked the neighbor to drop off the baby at his father's house after she went to work, but police alleged they claimed to forget he was in the car

Michelle Crandall, a friend of Phillips' parents Sean and Rita Holly, started a fundraiser to pay for Travis' funeral.

'Please help this family after their tragic loss of their 6 month old son and grandson. Anything helps,' she wrote.

Police will continue investigating and submit a report to the Yavapai County Attorney’s Office. The neighbor was charged as a juvenile and not named.

Seventeen children have died in hot cars around the US so far this year, plus another four whose cause of death is still to be determined.

They include another six-month-old child who died in Baton Rouge, Louisiana, on the same day after they parent forgot to drop them off at daycare and went to work, leaving them in the car.