SAN DIEGO (CNS) - A Rancho Bernardo man who shot his estranged wife following a marriage counseling session in a Scripps Ranch business park, then fled to Mexico before surrendering at the border, pleaded guilty Wednesday morning  to first-degree murder.

Jeremy Adam Green, 40, admitted his guilt a week before a preliminary hearing was to be held to determine if there was enough evidence for him to proceed to trial in connection with the death of 37-year-old Tressa Green.

The defendant is expected to be sentenced to 35 years to life in prison on Dec. 11.

At Green's arraignment, Deputy District Attorney Julie Lynn said the defendant and the victim went to the counseling session about 1 p.m. on June 6 at his suggestion.

When the session was over about 2 p.m., the victim tried to get in the passenger seat of the defendant's car, and he went to the trunk and retrieved a shotgun and shot her, Lynn said.

While his wife was on the ground, the defendant shot her two more times and left her for dead, then fled, the prosecutor said. He drove to the border, changed his shirt and put on a baseball cap before walking into Mexico, Lynn said.

Green was arrested June 12 at the San Ysidro border crossing after voluntarily returning from Cancun, Mexico.

Several hours after the slaying, a passer-by found a shotgun underneath a freeway ramp in Marian Bear Park, roughly eight miles from the site of the shooting. Authorities have declined to say if it was the weapon used to killed the mother of three.

The couple had been married since 2005 and had two children together.

Tressa Green, who had filed for divorce in April, also had a child from a prior relationship.