WASHINGTON — Prosecutors have rested their case in the perjury trial of Roger Clemens.

The government called the last of its 24 witnesses today, concluding 19 days of testimony. The last witness was a toxicologist from the FBI who testified about the various forms of vitamin B12.

Including jury selection, the trial is now in its seventh week. It was originally expected to take four to six weeks.

Clemens’ lawyers say they will need about two weeks to call their witnesses.

Clemens is charged with lying to Congress in 2008 when he denied using steroids and human growth hormone during his 24-year major league career.

The government’s case relies heavily on Clemens’ former strength coach, Brian McNamee, who testified that he injected the ex-pitcher with both substances.