Taxpayers paid a government worker at the U.S. Patent Office to play golf and pool, according to an investigation by the Commerce Department’s Office of Inspector General (OIG) that found nearly half of the employee’s billed hours were fraudulent.

The employee, who worked as a patent examiner in the U.S. Patent and Trademark Office (USPTO), earned over $70,000 a year despite “egregious time and attendance abuse,” which was not checked by managers at the office. The employee, referred to in the report as “Examiner A,” resigned after learning of the OIG’s investigation.

“According to the evidence, Examiner A received payment for over 18 full weeks of work, in aggregate, that he did not actually work,” the audit said. “Ultimately, USPTO management’s system of internal controls did not detect Examiner A’s time and attendance abuse; to the contrary, these issues did not come to light until a whistleblower submitted anonymous notes to the examiner’s supervisor and another manager.”

The anonymous letter in August 2014 that sparked the investigation said the employee “never shows up to work,” “seems to get away with anything,” and that he would only come into the office at the end of every quarter to submit “garbage” work.

“The note questioned how the supervisors could ‘allow this type of behavior’ to occur and why Examiner A had not ‘been fired by now for performance,’” the OIG said.

In all, the employee “committed at least 730 hours of time and attendance abuse, resulting in the payment of approximately $25,500 for hours not worked in FY 2014 alone.” The majority of the hours he did not enter the office building, or use his government-issued laptop.

The abused hours accounted for 43 percent of the employee’s total hours for the year. The hours amounted to 91 eight-hour workdays, or roughly 3 months. The OIG recorded 58 full workdays where there was no evidence that he entered the building.

However, the OIG said the employee likely got away with being paid for more hours he was not working because the employee was “given the benefit of the doubt.”

The employee was paid for full days of work, even though he often left to “hit golf balls at Golf Bar, play pool, or socialize at restaurants.”

The OIG examined instant messages between the employee and his coworkers about hitting the driving range.

One message occurred just before 1 p.m., after the employee spent less than 3 hours at the USPTO office.

“Ok, did u wanna [hit golf balls at Golf Bar] today at all?” he said. His coworker replied, “actually yeah, let’s just go there now?”

“I’ll walk over lemme just hit the restroom,” the employee said.

The other employee also said he was probably leaving soon anyway, saying, “godda go watch walking dead, etc.”

On another occasion the employee tried to convince a colleague to leave to play pool because he was “bored,” but they declined because they were “writing up a case.”

“Call me later if you wanna chill,” he said.

The USPTO did not review the employee’s time and attendance records despite “numerous red flags” the OIG said. The employee also was not fired despite receiving an “unacceptable” performance rating in 2012, 2013, and 2014, and “numerous complaints” about his work.

The employee’s supervisor said he “never suspected” that he was violating work policies, and cited that numerous employees at the USPTO have flexible work schedules that allow telecommuting.

The OIG has found attendance abuse in the agency before. Paralegals working for the agency were “paid to do nothing,” passing their time watching Netflix, doing laundry, and shopping online, costing taxpayers at least $5 million.

The audit warned that telework abuse could be widespread, given that nearly 10,000 patent office employees work from home at least once a week, and 5,000 work from home full time, or four to five days each week.

“While this report presents a case study of only one individual’s time and attendance abuse at USPTO, it illustrates the difficulties in preventing and detecting such activity in USPTO’s geographically dispersed workforce,” the OIG said.

“Although the USPTO has touted the benefits of its telework program, such as a reduction in rent, increases in employee satisfaction and retention, and a workforce much less affected by severe weather and traffic, this and other OIG efforts show that these programs also carry risks for abuse,” they said.

The OIG said the agency should try to recover the $25,500 in fraudulent pay through the legal system.