SACRAMENTO (CBS SF) — A man admitted Thursday to illegally manufacturing semi-automatic rifles at a metal shop in an industrial neighborhood in North Sacramento.

Sacramento resident Daniel Albert Crowninshield, also known on gun enthusiast forums by his online moniker “Dr. Death,” plead guilty Thursday to using computer-controlled machines to churn out parts for automatic rifles and other firearms without a license to do so.

Without conducting background checks, complying with required waiting periods, or completing firearm transaction paperwork, Crowninshield would sell the unregistered, AR-15-style firearms online to members of the public, according to the plea agreement.

Crowninshield, working out of his own metal shop, C&G Tool Inc., was arrested in 2014.

“Daniel Crownshield aka Dr. Death owned and operated a machine shop where he allowed customers with unknown backgrounds to use his machinery to unlawfully manufacture firearms for profit,” said Bureau of Alcohol, Tobacco, Firearms and Explosives Special Agent in Charge Jill A. Snyder.

According to investigators, Crowninshield would actually get the customer to press the button on the machine so that, technically, the customer would be manufacturing the firearm, not the machinist.

In 2013, an undercover agent conducted a purchase at C&G Tool and recorded both audio and video of the manufacturing process. At no point did Crowninshield require the undercover agent to fill out paperwork or go through a background check. The firearms also did not come with any serial numbers or manufacturer’s markings, according to court documents.

Crowninshield plead guilty Thursday to two of the six counts filed against him; unlawfully manufacturing and dealing in firearms and the possession of an unregistered firearm, an AK-47.

One of the government’s main concerns with Crowinshield’s manufacturing business was that the unmarked firearms he helped produce his could easily be used in violent crimes and would be very difficult, if not impossible, to trace back to the perpetrator of the offense.

Crowninshield apparently advertised his services on at least one online forum for firearm enthusiasts under the Dr. Death alias. A search of his shop by investigators uncovered a tool chest labeled with “Dr. Death” as well as emails with that moniker.

Following the search of his shop, Crowninshield went onto the forum and recommended two other firearm machinists in Sacramento to his customers before shutting down his operation.

The plea agreement requires Crowninshield to forfeit dozens or guns, firearm parts and assorted ammunition. It also requires him to hand over the machinery he used to manufacture the parts.

Crowninshield is scheduled to be sentenced on June 30th and faces a maximum statutory penalty of 10 years in prison and a $250,000 fine.

By Hannah Albarazi – Follow her on Twitter: @hannahalbarazi.