Rep. Elijiah Cummings of Maryland died Thursday morning at age 68, according to his office.

He died of “complications concerning longstanding health challenges,” his office said in a statement.

The Democratic congressman has represented Maryland’s 7th Congressional District since 1996 and served as the chairman of the House Oversight and Reform Committee, which is one of the committees involved in the impeachment inquiry of President Donald Trump.

As chairman of the Oversight Committee, Cummings oversaw a range of investigations into the Trump administration, from issues relating to the impeachment inquiry to the treatment of migrants at the southern border to the use of personal email for official use by White House officials to how the citizenship question was considered for the US census. And it was his committee that grilled Trump’s former personal attorney, Michael Cohen, in a blockbuster hearing this past February.

Cummings was born and raised in Baltimore — the city that is home to his district. The son of former sharecroppers, Cummings was born in 1951 and graduated from Baltimore City College High School in 1969.

He practiced law and served for 14 years in the Maryland House of Delegates, where, according to his congressional website, he became the first African American in Maryland history to be named Speaker Pro Tem.

In 1996, he was first elected to the US Congress. Cummings was reelected last year in the 7th Congressional District with 76% of the vote.