In this context, it sounds like the "aide" is an accomplice (accomplice = a person that helps someone commit a crime)

Having just read this story, maybe I can help! The first answer is correct in that the aide is an accomplice to the theft. However, both thieves stole from the law firm they worked at, so here, aide might refer to the person's position within the firm, for example, they were the aide to the lawyer. The article isn't clear on that, so unfortunately, the headline might just have been poorly written or used the word 'aide' as it is shorter and carries a similar meaning (often editors will look for synonymous words that fit within the constraints of print space).

You would need to read the rest of the article to know. Headlines rarely tell the whole story. What's not clear is if the 'aide' is the aide to the thief, or an aide to someone else. It's ambiguous without more context. It would be unusual to call an accomplice an aide, so my guess is that (s)he is an aide to someone or something else. Perhaps the aide had an agreement to help the thief get into wherever they work, in exchange for a share of the profits, and when they disagreed, the thief reported the aide, and told (the police or the employer?) that the aide had helped them.

The thief went to the authorities to turn his assistant in after a disagreement.

The article was about robbery that occured when the lawyer goes out to meet their parents and during that time thief took all the money and jewellery.when she comes back and when she checks her safe she cames to know that robbery had occured she make a compain and police catches one suspect and by coaxing him he told their was another person involved in robbery that person agreed to share profit him but then he betrayed him(suspect) and then cops cought that another person. (This was in brief about the article)