HOUSTON -- Austin County deputies said they are working around the clock to find the killers of a prominent Houston doctor and released pictures of the getaway vehicles, KPRC Local 2 reported Monday.

Dr. Jorge Mario Gonzalez, 56, was shot to death Saturday after five intruders came into his weekend ranchhouse near Bellville in Austin County.

Investigators said the motive could be burglary, but they are not sure.

The doctor's 29-year-old wife and 2-year-old son were also home, but apparently hid from the intruders. One of his ranch hands was also shot. He was hospitalized in stable condition.

"He gave a statement. We're analyzing the statement to make sure it goes in line with what was observed at the crime scene," said Sgt. Adolphus Pressley with the Texas Rangers.

Officials said Gonzalez and his family had just arrived home and were walking up to the ranch when they were confronted by three to four young men.

Austin County sheriff's deputies released pictures of the intruders' vehicles. One is a white, late 1990s Ford F-150 extended cab, long wheel base pickup truck without a front license plate. The other was described as a dark red Acura or Honda.

Investigators also released a picture of a silver Lexus, which they said belonged to a possible witness.

The pictures were captured by a deputy's dashboard camera soon after the doctor was killed.

Officials said someone from the white pickup truck fired on an officer responding to the 911 call. The officer was not hit.

Deputies said they believe five men were involved in the killing. Investigators have not released descriptions of the men.

Gonzalez had three grown children from a previous marriage. A son said he hopes someone will come forward with information to solve the case.

"I lost a loved one," Juan Gonzalez said. "He's a caring dad. He's a husband. He's got kids, grandkids. Please, anyone, please call police."

Jorge Gonzalez was chief of critical care at The Methodist Hospital in the Texas Medical Center.

Anyone with information is asked to call the Austin County Crime Stoppers at 979-865-2949. A $3,500 reward is being offered in the case.