THE REPORT IS ONE OF A SERIES CONCERNED WITH ASSESSING LABORATORY ANALYSIS OF PHYSICAL EVIDENCE. THE LABORATORIES WERE TOLD THAT A VICTIM HAD HAD ARGUMENTS WITH FELLOW WORKERS AND THAT IT WAS SUSPECTED THAT ONE OF THE WORKERS HAD SENT THE QUESTIONED DOCUMENTS: A THREATENING LETTER AND AN ENVELOPE. USING SAMPLES OF HANDWRITING FOR FOUR SUSPECTED EMPLOYEES AND TYPEWRITING SAMPLES FROM THREE TYPEWRITERS AT THE PLACE WHERE THE VICTIM AND SUSPECTS WORKED, THE LABORATORIES WERE TO DETERMINE WHICH, IF ANY, OF THE SAMPLES MATCHED THE TYPING AND HANDWRITING IN THE QUESTIONED DOCUMENTS. SIXTY-SIX OF THE LABORATORIES SINGLED OUT THE SUSPECT WHO EXECUTED THE HANDWRITING IN THE QUESTIONED LETTER, AND 66 CORRECTLY IDENTIFIED THE TYPEWRITER USED TO PREPARE THE QUESTIONED ENVELOPE. THESE AND OTHER DATA ARE REPORTED IN TABULAR FORMAT WITH NO NARRATIVE INTERPRETATION. BREAKDOWNS OF RESPONSES FROM INDIVIDUAL LABORATORIES ARE INCLUDED. AN EXPLANATION OF SURVEY METHODS AND A COPY OF THE SURVEY INSTRUMENT ARE PROVIDED. OTHER PROFICIENCY TESTS ARE DOCUMENTED IN NCJ 47522-47540 AND 47542. (LKM)