Janet left fingerprints on the glass, the detectives were able to solve the crime.

Janet left fingerprints on the glass so the detectives were able to solve the crime.
Janet left fingerprints on the glass; consequently, the detectives were able to solve the crime.
Janet left fingerprints on the glass, consequently, the detectives were able to solve the crime.
Janet left fingerprints on the glass the detectives were able to solve the crime.

my answer
Janet left fingerprints on the glass; consequently, the detectives were able to solve the crime.

Right.

Yes, that is correct. The sentence "Janet left fingerprints on the glass; consequently, the detectives were able to solve the crime" is grammatically correct and conveys the cause-and-effect relationship between leaving fingerprints on the glass and the detectives solving the crime.

Your answer is correct.

The sentence "Janet left fingerprints on the glass; consequently, the detectives were able to solve the crime." is the correct sentence.

The addition of the coordinating conjunction "consequently" helps to show the cause-and-effect relationship between Janet leaving fingerprints on the glass and the detectives being able to solve the crime. The semicolon (;) is used to join two independent clauses that are closely related in meaning.