A federal grand jury here is making a renewed effort to pinpoint the identity of the individual who arranged a jury tampering attempt that led to the declaration of a mistrial in the first political corruption trial to suspended Maryland Gov. Marvin Mandel, according to informed sources.

Yesterday, Walter E. Weikers, the Baltimore furniture salesman found guilty 21 months ago of attempting to bribe a juror in Mandel's first trial, appeared before the grand jury for several hours.

Weikers arrived at the office of U.S. Attorney Russell T. Baker accompanied by his daughter Susan and by Harold Glaser, his attorney in the 1977 jury-tampering trial.

Neither Glaser nor any attorney in Baker's office would comment on Weiker's appearance before the grand jury yesterday, but it was learned that the case was presented to the grand jurors by Barnet D. Skolnik, the Asst. U.S. attorney who prosecuted both the Mandel and the Weikers cases.

Skolnik is scheduled to leave the Justice Department and start in private practice this week.

The 69-year-old Weikers was convicted in February 1977, of obstruction of justice for offering a $10,000 bribe to Mandel juror Oscar Sislen, a distant relative. Sislen reported the attempt to the presiding judge in the case, and was removed from the jury panel.

However, when several of the remaining jurors overheard news reports about the bribe attempt U.S. District Court Judge John Pratt declared a mistrial in the case.

Weikers served about 18 months in a federal penitentiary before his release in September. He had consistently denied that he offered the bribe, saying instead that the juror had solicited it.

Since Weikers had been convicted in connection with the case, he would not be able to refuse to testify based on his constitutional protection against self-incrimination.

If he refused to talk to the jury or lied about the incident, he could be subject to further prosecutions.

Prosecutors have said since the jury-tampering attempt was revealed to it by an individual they referred to as the "shark" who they said was trying to subvert the prosecution.