Police are trying to find Greg Franta, a Boulder architect who worked with former President Bill Clinton to make the White House more energy efficient. The senior vice president did not show up for work at the Rocky Mountain Institute Monday, after dining with a family member the night before. He was reported missing on Tuesday, according to the Daily Camera, and was last spotted in the 6700 block of Federal Boulevard around 1:30 a.m. Monday, business surveillance cameras in the area indicate.

Franta was driving a 2006 white Honda Civic hybrid with a ski rack and sticker that reads “hybrid electric.” There’s no evidence anything criminal happened, according to Boulder police, who are cooperating with other agencies and treating Franta’s disappearance as a missing persons case.

Llewellyn Wells, vice president of communications and media at the company, calls Franta a “pioneer” in the green-building movement in the United States, particularly in making it affordable. Franta has worked on projects across Colorado and around the world, according to his online bio.