The U.S. Attorney's Office for the District of Columbia never prosecuted Michigan man Dale Paul Melvin after he drove his Chevy Tahoe onto the sidewalk of the U.S. Supreme Court near the U.S. Capitol last October.

It's unclear why the case is still up in the air. 

Melvin returned Thursday to Capitol Hill, but was cooperative with officers, Fox News is told. He got out of his vehicle and talked to officers, and U.S. Capitol Police did not arrest Melvin Thursday.

Dale Paul Melvin Supreme Court

Parked in front of the Supreme Court illegally, Dale Paul Melvin talks with U.S. Capitol Police officers Feb. 3, 2022, in Washington. (Drew Angerer/Getty Images)

Police did arrest Melvin on Oct. 5, 2021, after a standoff that lasted several hours. Melvin refused to speak with police in the fall, saying "the time for talking is done." He was eventually pulled from the vehicle and charged with disobeying police and assault on a police officer. 

TWICE-DEPORTED CRIMINAL ACCUSED OF DRAWING SWASTIKAS AT DC UNION STATION PROTECTED BY BIDEN POLICIES

Fox News is told there was nothing to charge Melvin with Thursday. 

Dale Paul Melvin Supreme Court

U.S. Capitol Police arrest Dale Paul Melvin, who parked a vehicle outside the Supreme Court in Washington, Oct. 5, 2021. (Jim Watson/AFP via Getty Images)

"It’s alarming he’s back today," said one senior source. 

This isn’t the first time Capitol Hill security officials have had trouble with repeat offenders. 

IS THE US CAPITOL SAFER TODAY THAN ON JAN. 6?

In the fall 2015, Capitol Police arrested Larry Russell Dawson after he began screaming about being "a prophet of God" inside the public gallery of the House chamber.

CLICK HERE TO GET THE FOX NEWS APP

In 2016, Dawson returned to the Capitol and tried to get inside with a fake Beretta. Capitol Police shot and wounded Dawson. He was charged with assault with a deadly weapon.