A U.S. District Court jury here acquitted a former FBI agent yesterday of the charge that he tried to burglarize the bureau's credit union office at the J. Edgar Hoover Building in April 1980.

The jury deliberated about eight hours before finding H. Edward Tickel, 42, once one of the bureau's top experts in court-ordered break-ins and safecracking, not guilty of the charge.

Tickel, speaking to reporters after the verdict, said he "came close to being railroaded today. I know I didn't do anything wrong."

The FBI began an investigation of the agent, a 13-year veteran, after a janitor found him in the darkened credit union office with the vault door open shortly after the office closed on April 16, 1980. That was the day before payday at the bureau, when about $260,000 was in a safe inside the vault.

During the two-week trial, Tickel, who also served as a locksmith in the headquarters, testified that he went to the credit union because he got an anonymous phone call from someone who said the doors to the credit union had been left open.

Tickel was fired from the FBI after his indictment here last November on the attempted burglary charge and on charges that he stole four walkie-talkies from the FBI. His trial in the second case is still pending.

Tickel also was indicted last November by a federal grand jury in Alexandria on charges of interstate transportation of diamonds stolen from a North Carolina jeweler, obstruction of justice, income tax evasion and soliciting perjury. He is scheduled to stand trial on those charges on Feb. 28.

Tickel has pleaded not guilty to those charges, and his lawyer, Kenneth Michael Robinson, has said in interviews that the diamonds were not stolen but had been in Tickel's family for some time. Robinson has said that the charges of obstruction of justice and solicitation of perjury are unfounded.

Robinson said the jury acquitted Tickel because of his testimony in explaining the incident and because of the character witnesses from the FBI who testified in Tickel's defense. The prosecutor, Assistant U.S. Attorney John P. Hume, declined comment.

Tickel, who showed no emotion when the verdict was read, said that the experience of "being on the other side," made him "feel sorry for people who don't have the resources I had or the friends I had" to defend himself.