car. Johnson and Boyd then directed the agents to drive to another house.  During the drive, Johnson offered to sell the agents machine guns and hand grenades.  At their destination, Johnson exited, entered a house, and returned with an object wrapped in a brown paper bag.  He gave the bag to Boyd, who handed it to Shrodes.  The object was a sawed-off shotgun.  After Boyd and Johnson settled on the price, Shrodes paid Boyd $60 for it.


4
On cross-examination, the defense attempted to discredit Shrode's identification of Johnson.  This was countered on redirect, when Shrodes, over objection, was allowed to relate the conversation that took place at the time of Johnson's arrest.  On February 8, 1977, Shrodes went to the address wherehe had picked up Johnson in April and asked for Duck.  Johnson appeared.  Shrodes then identified himself as Jimmy D., and said, "You remember I was, you know, with White Folks," and Johnson answered, "Yeah."  This testimony was corroborated by agent Thomas C. Doyle, who accompanied Shrodes.


5
The only other government witness was a United States Marshal who testified, in his capacity as witness security contact man, that the informant was no longer in the witness protection program and that the Marshal Service was unaware of his whereabouts.  Johnson took the stand and denied being with Boyd or possessing a sawed-off shotgun on April 26, 1976.

Absent Witness Instruction

6
The propriety of giving an "absent witness" instruction, directing the jury that failure of the prosecution to produce