WASHINGTON, Feb. 4 (UPI) -- An encounter a Colorado man had with U.S. Vice President Dick Cheney could result in the unprecedented testimony of a sitting vice president, a report says.

Steve Howards, 55, claims he touched the vice president on the shoulder during an encounter in Colorado regarding Iraq, and the Secret Service responded with a summons for misdemeanor harassment charges, The Washington Times said Monday.

Secret Service agent accounts vary, from a light touch during a handshake to a shove. One agent described Howards reaching over children to strike the vice president.

Howards argues the various accounts of the event by the agents suggest Cheney himself should testify in a rights violation case Howards filed.

Cheney attorney James Gilligan said to get the vice president to testify, Howards must show Cheney has information that is not obtainable elsewhere.

Gilligan noted the Secret Service and other government employees filed depositions in the case, but said getting Cheney to do so "is a different kettle of fish."

A judge ordered Gillian to file a brief by the end of February stating why Cheney should not be subpoenaed.