To become a detective in Qatar, you will need to follow these steps:

1. Meet the Eligibility Requirements: To become a detective in Qatar, you must be a Qatari national and have a degree in law or criminology. You must also be at least 21 years old and have a clean criminal record.

2. Gain Experience in Law Enforcement: Before becoming a detective, you will need to gain experience working in law enforcement. This can include working as a police officer, security officer, or in another related field.

3. Apply for Detective Training: Once you have gained some experience in law enforcement, you can apply for detective training with the Ministry of Interior in Qatar. This training typically includes both classroom instruction and hands-on experience in detective work.

4. Pass the Detective Exam: After completing your training, you will need to pass a detective exam to become certified. The exam covers both written and practical skills, and it is designed to assess your competency as a detective.

5. Work as a Detective: Once you have passed the exam and received your certification, you can begin working as a detective in Qatar. This may include investigating crimes, interviewing witnesses, and gathering evidence to build a case.

Becoming a detective in Qatar can be a challenging and rewarding career path. It requires a strong commitment to law enforcement, excellent problem-solving skills, and the ability to work well under pressure. It's also important to maintain a high level of professionalism and integrity in all aspects of the job.