Did they do ANY fact-checking on Walz?

A former colleague of Tim Walz from the National Guard has alleged that a classified nuclear manual went missing around the time Walz returned from a trip to China, suggesting Walz, due to his access, might have been involved in its disappearance. The colleague, now retired, claims Walz was often the only one with access to where the manual was stored and has expressed willingness to cooperate with the FBI regarding this incident.