The Los Angeles County Sheriff’s Dept. (LACSD) accused two phony engineers of using stolen software to forge the engineering seal and signature of a former employer. The suspects, Wilfrido Rodriguez and Ruben Gutierrez, allegedly used the fake stamps to sell illegal drawings to hundreds of residential and commercial projects built throughout Southern California over 10 years.

Because the suspects are not licensed professional civil engineers, structures built based on their engineering calculations and specifications may be unsafe and not suitable for habitation, said Det. Ron Barton, LACSD, in a statement.

The investigation started in April 2014, when Palos Verdes Engineering Co. informed the sheriff’s fraud and cyber crimes bureau it suspected its two former employees of fraud.

The duo allegedly provided fraudulent structural engineering plans for residential room additions, single-family residences and two-story multi-unit duplexes.

The residential housing sector is particularly vulnerable to this kind of fraud, says Michael Cochrane, structural engineer and vice president at Thornton Thomasetti, Los Angeles. “Everybody’s trying to save a buck, so, a lot of times, plans are developed by non-engineers,” he says. “They might need a structural engineer to sign off on one beam of the house. It’s very low-tech.”

The sheriff’s department said the scam involved “several hundred” projects “in an estimated 56 Southern California cities.”

Rodriguez and Gutierrez worked as architectural and engineering drafters, so they had the basic knowledge to produce the drawings. “You’ve got to ask, ‘Where are the [city and county] plan-checkers?’ ” says David Cocke, principal, Structural Focus, Los Angeles. “A step must be missing somewhere.”

The forged civil engineering seal and signature used on structural engineering records made the plans appear authentic—as if they had been reviewed and approved by a licensed professional civil engineer.

“A real engineer needs to [assess] what the risks are … there could probably be a retrofit solution,” says Cocke.