 -- A Wisconsin man accused of threatening to carry out attacks in a manifesto sent to the White House allegedly stole 18 firearms, including a fully automatic M-16 assault rifle, while raiding a gun store last week, according to court documents.

A massive manhunt has been underway for Joseph Jakubowski since he allegedly robbed the Armageddon Supplies gun shop on April 4 near Janesville, a city about 60 miles southwest of Milwaukee. An apology letter to the gun store owner was found where Jakubowski had been living, according to court documents. The 32-year-old is still at large as of Wednesday and is considered armed and dangerous, according to the FBI.

A criminal complaint filed Tuesday in Rock County and obtained by ABC News charges Jakubowski with burglarizing the gun shop. Detectives of the Rock County Sheriff’s Office said surveillance video captured Jakubowski on April 4 at around 8:36 p.m. local time diving head-first through a broken window of the gun shop and loading multiple long guns, "handfuls of handguns" and several boxes of ammunition into a duffel bag, the court documents state.

Detectives observed Jakubowski on surveillance video exiting the gun shop with the duffel bag slung over his shoulder at approximately 8:40 p.m. local time. After speaking with the store owner and completing an inventory of items stolen, Rock County authorities determined that these items included 18 various firearms and two gun silencers. A fully automatic 5.56/.223 caliber M-16 rifle, as well as at least one other long gun, was among the weapons missing from the store, according to the complaint.

A vehicle identified as belonging to Jakubowski was found burning some three miles from the gun store shortly after the robbery, prosecutors said.

The criminal complaint lists the following three counts: "burglary – arming self with a dangerous weapon, felony theft – special facts and possession of burglarious tools."

Detectives spoke with Jakubowski’s sister on April 6 and confirmed he had been living with her until moving out the morning the gun shop was burglarized. The sister, identified only as N.J. in the complaint, told detectives she found "what appeared to be the draft of an apology letter to a gun shop owner" while she was cleaning out his room, according to the complaint.

In the letter, Jakubowski explained that he wanted to buy the guns to protect himself and his family but, as a felon, he was prevented from doing so. He apologized to the gun shop owner for stealing the weapons and thanked the owner for protecting the 2nd Amendment rights of U.S. citizens, the court documents state.

More than 150 state and federal law enforcement officers have been searching for the fugitive. As of Wednesday, authorities have received approximately 650 leads so far in their investigation, according to the Rock County Sheriff’s Office.

Rock County Sheriff Robert Spoden has said Jakubowski threatened to attack schools and public officials in the 161-page handwritten manifesto that he mailed to President Donald Trump. Jakubowski spoke of a "revolution" and “time for change” in a video recorded a week before the gun store robbery. The video also shows him dropping a package addressed to Trump into a mailbox.

On Tuesday, the FBI doubled the reward for information leading to Jakubowski's capture from $10,000 to $20,000. The FBI also released a digitally altered image of what Jakubowski would look like with his hair shaved off. Direct sightings of Jakubowski should be called into 911 immediately. General tips and historical information can be reported to the FBI tip line at 1-800-CALLFBI (225-5324) or the Rock County Sheriff’s Office tip line at 608-757-7911.

ABC News’ Adrienne Bankert, Jack Date, Michael Edison Hayden, Julia Jacobo and Jason Volack contributed to this report.