Unless the person doing the tainting was one step away from Welsh....someone very close.
Evidentally the envelopes did NOT travel through the mail in a torn condition, hence no poisoned postal workers. It's also pretty evident that the the Bill-Clinton-corrupted Arkansas state police force wasn't going to do anything about it. IMO it's not too much of a leap to think that the worst among the corruptees could have tampered with the envelopes right there in Welch's office and cleaned them up after the exposure was accomplished, hence no poisoned co-workers. Welch himself is proof that there are members of the Arkansas State Police who are NOT corrupt, but who do they turn to when something like this happens? The fish rots from the head down.
Investigator Wiley wrote down the names of Welch's medication and later confirmed that he was, in fact, being treated for anthrax. Other state police officers went to the hospital room, periodically, to help Debbie Welch, who stayed in the private room with her husband day and night for the entire 14 days that Welch was hospitalized. Investigator Charles Lambert and Investigator Bobby Walker were among those that heard the doctor discuss Welch's circumstances and the anthrax.
These men are further examples of integrity and personal loyalty within the Ark. State Police. Think for a minute what is meant by these officers 'helping Debbie Welsch' by periodically going to the hospital room where she was basically standing guard over her husband. Yeah, it helps emotionally to have friends drop by, but IMO they also posed a risk to anybody who might have happened by to be sure the 'job' on Welch got finished.