The serious car crash that sent 5-star hooper Alijah Arenas to the hospital with serious injuries was likely caused by excess speed, law enforcement sources tell TMZ Sports.

The Los Angeles Police Department was on the scene of the 5 AM crash, which occurred along a two-lane residential roadway in the Winnetka neighborhood of the San Fernando Valley, in a 40 MPH zone.

18-year-old Alijah was alone in the Cybertruck — owned by his father, ex-NBA star Gilbert Arenas — at the time of the accident … which was a single-vehicle wreck.

The fast-acting good Samaritans were able to free Alijah, who was then rushed to the hospital for treatment for smoke inhalation and other ailments, including bumps and bruises sustained during the wreck.

Good news, though … a rep for the Arenas family told us the top USC recruit, who many project will be a top 5 NBA draft pick next year, is already on the road to recovery!

Luigi Mangione might be facing serious charges, but outside court, you’d think he was a rockstar — with a wild crowd of supporters turning up ahead of his arraignment hearing Friday.

The scene outside NYC federal court was flooded with “Free Luigi” advocates who treated the accused like a hero — but not everyone was on board, with one fiery protester stepping up to blast the crowd for glorifying a man accused of murder.

Supporters were out with signs and some in Luigi video game character dress-up — making it crystal clear they believe Luigi’s alleged actions were justified, pointing to the countless lives they claim have been lost due to corrupt health insurance practices.

Luigi’s due in court today for arraignment, facing four serious federal charges — including murder with a firearm, two counts of stalking, and a weapons charge for allegedly using a silencer.

Luigi Mangione has just pled not guilty to four federal charges — including a count of murder through the use of a firearm.

The alleged UnitedHealthcare CEO killer appeared in a New York City federal court Friday for his arraignment, where he pled not guilty to one count of murder through the use of a firearm, two counts of stalking, and one firearms offense for allegedly using a silencer.

The judge ordered all discovery to be turned over to the defense within 30 days … making the deadline for that May 27.

As you know … federal prosecutors want to go after Mangione with the death penalty, while Mangione’s team has opposed it. They made their respective filings early this month.

As we previously reported … Mangione was arrested in December, days after he allegedly shot and killed UnitedHealthcare CEO Brian Thompson early in the morning on a New York City street.

The slaying started a multi-day manhunt … which ended when an employee at a Pennsylvania McDonald’s called the police on him.

Luigi is facing both state and federal murder charges for allegedly killing Thompson … and, he pled not guilty to state murder charges back in December.

Mangione’s alleged diary shows months of planning leading up to the murder … with one entry reading that “insurance is the target” because it “checks all the boxes.”

While some — like President Donald Trump — have slammed Mangione and his supporters, others, like journalist Taylor Lorenz, who’s faced controversy for her take on the case, are more on the fence about the alleged killer.