FAIRFAX, Oklahoma - The FBI needs help tracking down a man suspected of robbing four banks in seven days.

There is a federal arrest warrant for Jesse Leaverton, and agents say he is armed and dangerous.

The latest bank robbery happened in Osage County Friday morning. Authorities say he walked through the front door and acted like any other customer, but when he left, the doors were locked and only the drive-thru was open.

Investigators are dusting for fingerprints and gathering evidence after they say a man - who the FBI believes is Leaverton - robbed Security State Bank in Fairfax.

They said the robber waited in line then approached the teller.

"She said when he walked up to her he said ‘I'm not having a very good day today,'" bank president Tip Burts said.

That's when chief deputy Charlie Cartwright said the man slid the teller a note.

"He told he had a weapon and threatened to kill her," Cartwright said.

The teller handed the money over and the robber walked out.

The FBI said there have been three other similar robberies in the last week.

"The suspect was wearing similar clothing, was carrying a similar briefcase and made demands in a very similar way," Cartwright said.

On June 18, a robber hit Arvest Bank near Admiral and Memorial in Tulsa. Two days later, surveillance cameras captured what appears to be the same man in Missouri. Later that same day, Bank of America in Tulsa, near Sheridan and Admiral was robbed.

Then, Friday, Security State Bank in Osage County.

"He may have some addiction needs that are precipitating these robberies," Cartwright said.

Leaverton is a felon who was convicted of bank robbery in 2012. Authorities don't have any idea where he is located. They said he still could be in the area or possibly crossed state lines.

If you know Leaverton's whereabouts, call the Osage County Sheriff’s Office or the Tulsa Police Department's CrimeStoppers tipline at 918-596-COPS.

The Oklahoma Bankers Association is offering a $2,000 reward for a tip that leads to an arrest.