SAN FRANCISCO — The murder trial of a tech consultant in the stabbing death of Cash App founder Bob Lee begins Monday, a year and a half after the widely admired entrepreneur was found staggering on a deserted downtown San Francisco street seeking help.

On the first day of his murder trial Monday morning, lawyers for Nima Momeni, the IT consultant accused of stabbing Cash App founder Bob Lee, said Lee’s alleged cocaine use and sleep deprivation forced Momeni to “defend himself.

San Francisco prosecutors made opening statements Monday in the murder trial of a tech consultant charged in the stabbing death of Cash App founder Bob Lee, previewing a timeline of events before the death and attempts afterward by the defendant to hide what he did.

Lee’s death stunned the tech community, and fellow executives and engineers penned tributes to his generosity and brilliance. Lee was chief product officer of cryptocurrency platform MobileCoin