Aliso Viejo man pleads guilty to hitting and injuring a federal employee with his car in Laguna Niguel

An Aliso Viejo man pleaded guilty Tuesday to driving into a federal employee and crashing into a federal building in Laguna Niguel, apparently out of anger about a large IRS debt.

Geoffrey Donald Rickner, 48, admitted to one count of felony assault on a federal employee by use of a dangerous and deadly weapon and inflicting bodily injury, an offense that carries a maximum sentence of 20 years in federal prison, according to the U.S. Attorneys Office.

Shortly after 4:30 p.m. on March 3, 2016, Rickner “gunned” his Mercedes-Benz through an intersection in front of the south entrance of the Chet Holifield Federal Building – also known as the Ziggurat – in Laguna Niguel, according to prosecutors.

Rickner struck a U.S. Customs and Border Protection security specialist who was walking through the marked crosswalk, then drove through a metal garage door, coming to a stop when the vehicle struck a concrete wall inside the federal building.

The federal worker suffered “permanent and life-threatening injuries,” according to prosecutors, including head trauma, broken ribs, internal bleeding and badly damaged legs. He was hospitalized for three weeks, prosecutors added, and continues to suffer from “pain and physical impairment.”

In the hours leading up to the crash, Rickner’s suspicious behavior – including pacing and erratic driving – caught the attention of security guards at the building, who at one point detained him. According to court filings, Rickner owed the IRS more than $200,000, and had been suffering from an unspecified mental illness.

Rickner is scheduled to return to the federal courthouse in Santa Ana on Oct. 7 for sentencing.