A California man driving cross-country to the White House on a mission to “do whatever it takes” to kill top officials on a “hit list” that included President Biden and former President Barack Obama has been arrested in Iowa, the authorities said in court papers.

The man, Kuachua Brillion Xiong, 25, has been held since Dec. 23 at the Pottawattamie County Jail in Council Bluffs, Iowa, on charges of making threats against a former president, according to sheriff’s records.

Mr. Xiong began driving from his home near Sacramento on or around Dec. 18 “with the intention of driving straight to the White House in Washington, D.C., to kill persons in power,” Justin Larson, a Secret Service agent, wrote in a criminal complaint.

Mr. Xiong made it as far as Iowa. On Dec. 21, he was pulled over by a sergeant with the Cass County Sheriff’s Department “for driving aggressively, weaving in and out of traffic, and speeding,” according to the complaint. Officers who detained him noted that he was using Google Maps to map a route to 1600 Pennsylvania NW, Washington, D.C.

When the sergeant, Tyler Shiels, searched the car, he found an AR-15-style rifle, ammunition, loaded magazines, body armor and medical kits, according to the complaint.

Mr. Xiong told investigators that if he had not been pulled over, he would have continued traveling as part of his plan, which he said was a mission from God to “combat evil demons in the White House.” Mr. Xiong told investigators that he “believes that he is the only person remaining who can free the United States of evil.”

According to the criminal complaint, which was filed in Federal District Court for the Southern District of Iowa, Mr. Xiong assembled his hit list using the popular app TikTok, downloading videos “to compile a list of evil individuals he intended to kill.”

The list included over 100 videos and targeted — in addition to Mr. Biden and Mr. Obama — former President Bill Clinton; Dr. Anthony Fauci, the country’s foremost infectious-disease specialist; and Mark Zuckerberg, chief executive of Meta, the social media giant previously known as Facebook. Mr. Xiong said he would kill Mr. Biden only if he did not comply with Mr. Xiong’s demands, which were not specified in the complaint.

During the interview with officials, Mr. Xiong was adamant that if released from custody he would not return home to California to see his family and but would “do whatever it takes” to complete his plan. “He plans on dying while fighting evil demons at the White House,” Mr. Larson wrote.

In an email on Thursday, Mike Maloney, a lawyer for Mr. Xiong, declined to comment on the case.

According to court records, Mr. Maloney has signaled his intent to use an insanity defense in his client’s trial.