Larry Nassar, a sports doctor accused of molesting girls while working for USA Gymnastics and Michigan State University appears in court in Lansing, Michigan, where he pleaded guilty to multiple charges of sexual assault. File picture: Paul Sancya/AP

Washington - US marshals on Wednesday served a subpoena on former Michigan State University President Lou Anna Simon to compel her to appear before a US Senate subcommittee on June 5 on efforts to protect athletes from abuse, a committee spokesman said.

Simon, who resigned from Michigan State in January, and Steve Perry from USA Gymnastics were criticized for not doing enough to halt abuse by former doctor Larry Nassar, who was convicted last year of molesting gymnasts and was sentenced to an effective life term in prison.

It is extremely unusual for a congressional committee to resort to issuing subpoenas – and even more unusual to be forced to take the step of asking the US Marshals Service to serve a subpoena to compel an appearance.

Witnesses can assert the right not to answer questions if they fear the answers could be used against them in a potential criminal prosecution.

A lawyer for Perry, who resigned in March 2017, accepted a subpoena on his behalf, said spokesman Frederick Hill of the Senate Commerce panel that has been investigating abuse of athletes. Simon was served with a subpoena in Traverse City, Michigan, Hill said.

A lawyer for Simon did not immediately respond to a request for comment.

A third former official, Rhonda Faehn, who was the women’s program director of USA Gymnastics and was dismissed earlier this month, has also been called and agreed to testify, Hill said.

It was not immediately clear who is representing Perry or Faehn.

Earlier this month, hundreds of women sexually abused by Nassar tentatively agreed to a $500 million settlement with Michigan State University.

Kerry Perry, chief executive of USA Gymnastics since December, last week apologized to hundreds of female athletes who were sexually abused by Nassar and told a US House of Representatives subcommittee hearing that "those days are over."