It was one of the biggest surprises on Sine Die, the last day of the 2017 Maryland legislative session. And it had nothing to do with a bill getting killed or being sent to the governor’s desk.

Maryland Sen. Nathaniel T. Oaks (D-Baltimore), who is facing federal charges for allegedly misusing his legislative position and taking thousands of dollars in bribes, strolled into the ornate Senate chamber on Monday, patted one of his colleagues on the shoulder as he walked by and headed to his seat in the back of the chamber.

Wearing a seersucker suit and a matching kofi hat, Oaks walked into the chamber just minutes after Senate President Thomas V. Mike Miller Jr. (D-Calvert) acknowledged Oaks’s absence and publicly appreciated him for deciding to stay home.

“He’s not in jail,” Miller said earlier explaining Oaks’s absence about an hour after the session opened. “He said he didn’t want to be a distraction.”

Oaks moved to his seat next to Sen. William Smith (D-Montgomery), who wasn’t expecting his seatmate and had to clear a stack of papers sitting on the senator’s desk.

“I’m not cold yet,” Smith said Oaks told him as he sat down.

During a break, several lawmakers said they were shocked by Oaks’s decision to return on the final day.

Oaks is the third current or former Maryland lawmaker charged criminally since January, the start of the 90-day legislative session.

Del. Michael L. Vaughn (D-Prince George’s) resigned minutes before the start of the session in January and was later charged with involvement in a separate wide-ranging bribery scheme. Former Del. William A. Campos (D-Prince George’s) was also accused of accepting bribes in the federal investigation.

Oaks has served nearly 30 years in the General Assembly.

“I’m still a senator,” Oaks mumbled to a reporter when asked about his decision to return to Annapolis just days after turning himself into federal authorities.

According to court records, Oaks was introduced in 2015 to an FBI source who portrayed himself as a businessman looking to obtain contracts in Baltimore through a minority-owned company.

In the months that followed, Oaks had an assistant type up two letters on his House of Delegates stationery at the businessman’s request in support of what Oaks thought was a Department of Housing and Urban Development project, according to the court filing. Investigators assert Oaks knew the letters contained false statements about his involvement and knowledge of the project.

Oaks later introduced state legislation at the businessman’s request to fund up to $250,000 for the project, according to the court filing.

On Saturday, the General Assembly gave final legislative approval to a bill designed to strengthen the state’s ethics laws. The bill was part of Republican Gov. Larry Hogan’s legislative package.