One of the most difficult things we must determine in conducting a workplace investigation is, 'who's lying and who's telling the truth?'
In interviews, I always have an associate taking notes and acting as another observer.
In one investigation last year, I was interviewing an employee who accused another of sexual harassment. Significant harassment. After the interview, I told my associate that the accuser was in my opinion, completely empathetic and totally believable. My associate looked at me and said, "Are you crazy? She's lying through her teeth!"
As it turned out, my associate was right. (It's always good to have a female associate present when conducting an interview of a female - they can always tell!)
He said/she said scenarios are very difficult. The most an investigator can do is assess both sides and write up a report without a recommendation but with a slant on what we believe.
Louis DiLorenzo of Bond, Schoeneck & King, PLLC has written an article in Business Management Daily with which I completely agree - regardless of the obstacle of he said/she said, the investigation must go on.