A 20-year-old Indiana man who was found with guns and explosive chemicals in his car on the way to a California gay pride parade has been formally charged.

James Wesley Howell, who was ordered held on $2million bail, faces three felony counts of unlawful possession of an assault weapon, high capacity magazines, and explosives.

Howell told police he was headed to the pride festival in Santa Monica around 5am on Sunday, just hours after the Orlando massacre began. Authorities have said there is no apparent link.

James Wesley Howell (pictured left on Tuesday, right in mugshot) was found with guns and explosive chemicals in his car on the way to a California gay pride parade

Howell, who was ordered held on $2million bail, faces three felony counts of unlawful possession of an assault weapon, high capacity magazines, and explosives

There was increased LAPD presence at the event (pictured on Sunday), including undercover officers in the crowd. Howell's arrest came just hours after the Orlando shooting, but authorities said they were unrelated

Howell appeared at the Airport Courthouse in Los Angeles Tuesday, where he pleaded not guilty.

In addition to the three felonies, he also faces a misdemeanor for the possession of a firearm in a car.

Officers responded to reports of a suspected prowler knocking on a window and found Howell sitting in his white Acura on Sunday morning, according to the Santa Monica Police Department.

Santa Monica Police Chief Jacqueline Seabrooks initially wrote on Twitter that Howell told officers he intended to inflict harm, but she later said that information was inaccurate.

Other than telling officers he was going to the pride festival, Howell did not clarify what his intentions were, Lietenant Saul Rodriguez said on Sunday.

Howell was found with a high-capacity assault rifle, two other loaded rifles, magazines, a Taser, buck knife, handcuffs and security badge in his car when he was arrested.

Superior Court Judge Keith Schwartz said on Tuesday: 'I cannot in good conscience think of any reasonable reason that somebody would be traveling across the country with all of these things'

There was also a five-gallon container of gasoline in the white Acura, and a 25-gallon container of a commercially sold explosive that was two-thirds full, the LA Times reported.

The explosive Shoc-Shot is used as a firing target and consists of two components that are mixed together before it is used. The Shoc Shot found in Howell's car had already been combined.

Deputy District Attorney Sean Carney said gun enthusiasts don't mix Shoc Shot until it's ready to be used, as federal regulations require, and the amount that Howell had 'far exceeds any amount that would reasonably be used.'

The assault rifle in his car was also loaded with a 30-round magazine, which had another inverted 30-round magazine taped to it, according to police.

Howell recently drove from Indiana to Los Angeles because of pending charges against him in his home state, according to statements he made to police, and friends described him as a gun enthusiast with a short temper

Alone, each item found in Howell's car might not indicate anything sinister, Los Angeles County Superior Court Judge Keith Schwartz said. But together, they 'just don't pass the common sense test'.

'I cannot in good conscience think of any reasonable reason that somebody would be traveling across the country with all of these things,' he said.

Howell recently drove from Indiana to Los Angeles because of pending charges against him in his home state, according to statements he made to police.

Friends in Indiana described Howell as a gun enthusiast with a short temper. In October, he twice was accused of pulling a gun and making threats, once against his then-boyfriend and once against a neighbor.

Howell was convicted in April of misdemeanor intimidation for the incident with his neighbor. Under the terms of his probation, Howell was not allowed to have weapons or leave Indiana.

Howell's attorney, Pamela Jones, told the judge there was no evidence Howell planned to detonate the chemicals.

She said a black hood found in his car was 'just a clothing item,' and nothing indicated Howell planned to use it as a mask, as police contended was a possibility.

Howell was convicted in April of misdemeanor intimidation for the incident with his neighbor. Under the terms of his probation, Howell was not allowed to have weapons or leave Indiana. (Pictured, LA Mayor Eric Garcetti)

On Tuesday, the sheriff's office in Clark County, Indiana, said Howell also is the subject of a sexual assault investigation. The alleged incident occurred May 31 (pictured, the FBI on June 12 in Los Angeles, California)

Authorities have said Howell is completely unrelated to the Orlando massacre which claimed the lives of 49 people and injured 53 more in what is now dubbed the deadliest mass shooting in recent US history

James Wedick, a former longtime FBI agent, said the manipulation of the gun magazines would allow someone to reload 30 rounds in less than 2 seconds.

'It doubles your killing capacity by 100 per cent,' he said. For a civilian to have a weapon rigged as such, 'it suggests his purposes are deadly'.

The FBI took the lead in the investigation and its probe continues, spokeswoman Laura Eimiller said.

Federal agents searched Howell's Jeffersonville, Indiana, home Monday but declined to release any details.

On Tuesday, the sheriff's office in Clark County, Indiana, said Howell also is the subject of a sexual assault investigation. The alleged incident occurred May 31, about two weeks before Howell's arrest in California.

Howell can face a sentence up to nine years and four months if found guilty on all charges, the LA Times reported.