A 12-year-old boy was left behind at the scene of a fiery crash after an allegedly stolen vehicle crashed into a tree, police have said.

Emergency services were called to the intersection of Pendock Rd and Sherringham Rd in Cranebrook in Sydney’s west just before 7.30pm on Thursday following reports of a crash.

The car had allegedly crashed into a tree before catching fire.

Bystanders helped save the three male passengers – including a 12-year-old boy – from the wreck before it went up in flames.

The boy had suffered a broken leg and hip injuries during the crash and was treated by paramedics before being taken to Nepean Hospital.

He remains in a serious but stable condition.

However, police allege the two other passengers had already left the crash scene when they arrived.

One passenger was last seen fleeing on foot along Pendock Road, police allege.

The third passenger was allegedly carted into a shopping trolley and pushed from the scene by two men.

Later that night, paramedics were called to a home on Rosannah Way in Cranbrook after reports a man was heard yelling in distress inside the home.

Both paramedics and police were refused entry to the home.

The Public Order Riot Squad were called to force entry into the home, where they were allegedly met with two men and an aggressive dog.

Capsicum spray was used and a taser was deployed on the dog.

Inside the home, police located the third passenger, suffering from a broken leg and head lacerations.

Paramedics treated him before taking him to Westmead Hospital where he has also undergone mandatory testing.

He has yet to be formally identified but remains in a serious but stable condition.

The other two men – aged 40 and 55 years old – were arrested and charged with hindering or resisting a police officer in the execution of duty.

The dog was uninjured and left in the care of a neighbour.

Police allege the wrecked car was stolen from a Cranebrook home during a break and enter about 3.45am on Wednesday.

Specialist police from the Crash Investigation Unit have commenced an investigation into the circumstances surrounding the crash as well as attempting to identify the driver of the vehicle.

Anyone with information about the crash – or has any dashcam or mobile phone footage – are urged to contact Penrith Police Station or Crime Stoppers on 1800 333 000.

The 40-year-old man was refused bail and will appear at Penrith Local Court on September 21.

While the 55-year-old man was refused bail to appear at Penrith Local Court on September 14.