A Montgomery County tax assessor, who set out from his office Monday morning to make some routine house inspections, was found shot to death yesterday morning in the underground parking lot of the Unibank office building in Rockville where he worked.

Police said yesterday that 36-year-old George E. Angerman Jr., an assessor for the past seven years, had been bound, gagged with a red handkerchief, and shot once in the temple as he sat in the driver's seat of his silver Mercury Capri.

The body was found at about 8:40 yesterday morning by the assessment supervisor, Robert Rudnick, who was cruising through the underground parking lot looking for Angerman's car. A Maryland state medical examiner estimated yesterday that Angerman had been dead since about six p.m. Monday.

Rudnick pointed out that the worksheets Angerman had taken with him were not completed - an indication that he never made it to the house he was going to inspect.

Police said yesterday that the bullet that killed Angerman had apparently been fired from outside the car and had passed through Angerman's head before smashing through the car windshield, which was cracked on the lower right hand side.

The car doors were locked, but the window on the driver's side was half open when police found the car in a dimly lit portion of the lowest of five parking levels at the Unibank building. Employes of the tax assessor's office each pay $20 a month to park their cars there.

Angerman was first reported missing at about 9 p.m. Monday by his fiancee, Margaret Lindsey.

Linsey, who lived with Angerman in his town house in Shady Grove Village near Gaithersburg, became alarmed when Angerman failed to return home at the usual hour Monday night, according to neighbors. The couple and Angerman's daughter had planned to go to a movie, one neighbor said.

After telephone calls to local emergency rooms and to police produced no information, Lindsey waited up all night for Angerman, neighbors said. Early Tuesday afternoon as police questioned Lindsey at the town house, a porch light still burned above the door.

Angerman and Lindsey, who neighbors said had lived together at 8 Prairie Rose Ct. for more than a year, had planned to be married Aug. 26 in Bethany Beach, Md., where his mother has a home, friends said. The couple had selected a church and a minister, planned a crab feast for reception and ordered wedding invitations, friends said.

Neighbors described Angerman as a congenial man who was methodical in his habits."He always left for work at the same time and came home at the same time," said one neighbor.

When Angerman didn't arrive Monday night, Lindsey at first thought thunderstorm, but as the storm passed and Angerman didn't call, she became increasingly concerned, another neighbor said.

According to neighbors, there was little in Angerman's life to suggest why he might have been methodically murdered. A tax assessor who earned slightly more than $18,000 a year, he apparently lived a pleasant but modest life. A financial statement filed in June 1977 when he divorced his first wife, Charlene, listed his net worth as $19,073. The most valuable asset listed was his house, which he valued at between $43,000 and $54,000.

"He was Joe American," said one neighbor.

Friends described him as a man whose principal interests included sports and his 7-year-old daughter, Melanie. Angerman enjoyed swimming, owned a small sailboat, took vacations to scuba dive, jogged with his fiancee and had taught his daughter how to ski, they said.

He shared custody of his daughter with his former wife, who also lives in the Gaitersburg area. The Angermans, who were separated in 1975 and divorced in Aug., 1977, maintained reasonably amicable relations, neighbors said. During the school year the child's mother had custody and Angerman spent weekends with his daughter. During the summer, the arrangements was reversed. "She was really close to her father," said one neighbor of the child.

Late yesterday morning, Angerman's former wife came to take the child to her house as friends and neighbors were notified of Angerman's death. Angerman's father died last winter, and his mother was in California yesterday where she had gone for a younger son's wedding, friends said.

Angerman grewup in Washington and attended American University, according to neighbors. He later attended the University of South Carolina, one neighbor said.

His fiancee, works at Comsat.

John Yokay, one of Angerman's fellow workers, said he saw Angerman Monday morning and that he was carrying his map book of Montgomery County and some work sheets on which are recorded information concerning homeowners of a particular area and their house assessments.

Nathan Pomerantz, who often worked as Angerman's partner over the past few months but was not with him Monday, said Angerman was headed for the Glenfield Manor subdivision. He said Angerman had been busy preparing some routine tax court cases recently. He was assigned to assess the area of North Silver Spring and wheaton.

Rudnick, Angerman's supervisor and a close personal friend, said Angerman's fiancee had called him around 9:15 p.m. Monday. Rudnick was not at home, so she left a recorded message on his telephone answering machine, asking if Rudnick had seen Angerman.

She had reported Angerman's disappearance to the police at about 9 p.m., Rudnick said.

When Rudnick went to work Monday morning, he drove his car around level 2 P of the parking lot, where Angerman usually parked, and saw the body. He immediately went to his office and called the police, he said.

Rudnick and George Andrews, assistant supervisor in the assessment office, said Angerman had never spoken to them about receiving threats on his life.

Neighbors said Angerman had mentioned no financial problems nor expressed any other reason for concern.

Angerman's coworkers said he received a normal amount of complaints as an assessor, but that he had a knack for calming irate taxpayers and winning them over to his side.

"He wasn't the type to get angry and people didn't get angry at him," said Pomerantz.

"I can't imagine George as having enemies," Rudnick said. "As close as we were, he would have shared something like that with me," said Rudnick, who had been on vacation in the Bahamas with Angerman and his fiancee last April.

Police said yesterday they have no suspects in the murder and have not yet been able to determine the caliber of the murder weapon.

Police found a billfold on the console between the bucket seats in the car, which contained his assessor's identification and drivers' license.

The car keys had been left in the car, police said.