An FBI handwriting analyst testified yesterday in a rape and robbery trial that defendant Timothy Joseph Buzbee "probably" signed his own name on a credit card slip charged to an Exxon credit card allegedly stolen from an Aspen Hill rape victim.

The signature had been obscured by a second name, which prosecutors contend is a phony name, that was signed on the same line, FBI agent Edward Ball said. Ball testified he discovered only Wednesday what he believes "is probably Timothy Buzbee's signature" as he was reviewing enlargements of the charge card slips he had analyzed for prosecutors.

Police have testified they found the Exxon credit card in Buzbee's desk at work, and the prosecutors have asserted they will prove through Ball's handwriting analysis that Buzbee used the card, signing phony names on several charge card slips. Because the victim has been unable to identify her attacker, the prosecution has focused on the Exxon card to connect Buzbee to the crime.

Ball's discovery of what he believes is Buzbee's signature on one of the slips came as a shock to both the prosecution and the defense in this, the second Aspen Hill rape trial.

After learning of Ball's discovery, defense attorney Reginald W. Bours III began working feverishly to keep the new evidence out of the trial, arguing he had made critical pretrial decisions based on the evidence he knew about, which included nothing about a Buzbee signature.

After his motions to suppress the evidence were denied, Bours moved for a mistrial in the case during a conference among the lawyers and Circuit Court Judge John F. McAuliffe held at the bench and out of the hearing of the public. McAuliffe, who is presiding at the trial, denied his motion, and Ball was called to testify.

Ball said he had studied 10 Exxon charge card slips submitted to him by police. The slips had been sent to the rape victim in Exxon bills after her card allegedly was stolen. Ball compared the signatures and license tag numbers printed on the slips with samples of Buzbee's writing seized during police searches and other samples Buzbee was ordered to write at the prosecution's request.

Ball testified yesterday the signatures on eight of the slips "may have been written by Timothy Buzbee." The slips were signed with the last name of the rape victim, and various male first names.

Ball also testified the license tag numbers written on two of the slips were "probably written by Buzbee." On two other slips the numbers "may have been written by Buzbee," he testified, and on four others "differences from Buzbee's writing indicate they might have been written by someone else."

Prosecutor Bob Dean then led Ball on to a discussion of the slip with the two signatures. Ball had testified earlier the two signatures "tended to obscure one another," and he initially had no opinion on who had written them.

On Wednesday, however, in reviewing the enlargement of the slip, Ball testified, "I noticed that when it was blown up three times (its original size) I could observe what was written in that area."

Under cross-examination by Bours, Ball said he had made the discovery while Bours was conducting an interview with him Wednesday in order to prepare for questioning at trial.

Ball acknowledged he had previously told Bours the double writing on that slip was "illegible," and he had not called for enlargements of that slip when he was doing his analysis last October and earlier this month.

Bours suggested another name might be deciphered on the slip, asking Ball, "Don't you agree it looks like the name Ralph?"

Ball replied, "I would not."