DC tech entrepreneur Minh Nguyen was charged with first-degree murder after shooting his ex-wife’s new husband in Ashburn. Loudoun County Police say Minh entered their home Thursday night and shot Corey Mattison. Two children were in the home at the time. Minh has been an adviser to companies like Toutapp, Contactually and Uppidy. He launched App Press in 2012. He was a part-time consultant to TandemNSI, an organization helping startups work with national security agencies. Founder Jonathan Aberman said Minh helped expand the organization’s contacts in the emerging entrepreneur community from May to October last year. “It’s very tragic, and very sad,” Jonathan wrote in an email. A controversial DC Tech Facebook post over the weekend linked to a site to raise money for Minh’s legal defense, but both the Facebook post and the collection page have been removed.

Update: Previous versions of this article noted Minh helped found Plaxo with Sean Parker. Those claims turned out to be false.