Their investigation doesn't make any sense and they'll have to drop it.
Since then, the investigation has made little progress and there have been few leads, the police say.
An investigation by 4,000 federal agents and 3,000 support personnel made major progress in the case.
Fowler was "happy that the investigation all came together and made sense".
But further investigation made it clear that a survey of the century's portraits was needed, he said.
An investigation made no specific finding of fault in the incident, the statement said.
The investigation made progress last August when one of the defendants told security officers about the group.
The incident and the subsequent investigation made the national media several times as the case continued to develop.
Walsh's investigations made more rapid progress than he can have expected.
I wish to point out that the investigations launched after this woman's death have not made any progress so far.