'Other forces informed'
The burglary happened overnight between 6 and 7 August at one of FTS' Kent premises, Mr Leppard said.
Items found at the scene have been sent for forensic testing.
Mr Leppard said: "We are keeping an open mind at this stage as to the motive behind the burglary.
"However, we and the company have informed other police forces."
A statement from the company said IT equipment, including a server, had been taken.
It said: "The server, which is security protected, contained administrative data and details of some case files in relation to FTS's forensic work.
"In the unlikely event that the server was accessed, none of the data stored on the server in any way compromises ongoing police operations."
The company said all data was restored within 24 hours in line with the firm's "business continuity measures".
"FTS is undertaking a full and comprehensive review of security across the whole company," it added.