A former attorney for the FBI pleaded guilty on Wednesday to doctoring an email in relation to the Bureau’s investigation of ties between President Donald Trump’s 2016 campaign and the Russian government.

Kevin Clinesmith, a former Assistant General Counsel for the FBI’s National Security and Cyber Law Branch, was assigned to provide legal support for the investigation. In 2017 he helped prepare applications to obtain renewed authority from the US Foreign Intelligence Surveillance Court to “conduct surveillance” on an individual from Trump’s campaign, alleging “there was probable cause that [the individual] was a knowing agent of a foreign power, specifically Russia.”

According to documents filed in the US District Court in for the District of Columbia, Clinesmith received an email from a liaison in another government agency about the individual. He then “add[ed] the words ‘and not a source’ to the email, thus making it appear that the agency liaison had written in the email that [the individual] was not an [agency source].” Clinesmith forwarded the amended email to a colleague. The FBI ultimately relied on the email in its fourth and final application to the Surveillance Court.

Clinesmith pleaded guilty to “[making] and [using] a writing or document, specifically an email, that contained a statement or entry he knew was materially false; and that in doing so [he] acted knowingly and willfully.”

The sentencing guidelines for False Statements call for, among other things, imprisonment for up to five years and a fine not to exceed $250,000.