I was thinking about it that why can't the police put off their siren and catch the thieves off guard?
Why must they always make noise and signal to the bad people from miles away?
Is there any reason for that?

Like I'm 100% sure if I want to catch a thief,i will be as quiet as possible in order to prevent the thief from escaping or even knowing I'm coming to catch him or her.
Why can't police do the same thing?

Mojamosa Laa MO akinkanju l'oju Ogun

Ftc

Lalasticlala

Simple. So that the thieves will hear it and escape.

On the surface it seems better to quietly catch them redhanded . But the real reason they put on sirens is to scare away the criminals thereby preventing them from completing the crime. For example if someone is in the process of trying to kill his victim and hears the siren, he's most likely to stop immediately and run away, this helps saves the victim's life which is more important than catching the criminal after he has killed the person.
Secondly sirens help to clear the way for emergency response in normal civilized places, though this hardly works in places like Lagos where ignorant drivers will be dragging road with ambulances and police vehicles. They only respect army vehicles with koboko sticking out

To alert the normal people to stay clear to avoid obstruction or innocent being hurt.

Just like an ambulance on an emergency.
they do so to alert road users to pave way for traffick, create tension to psychologically weaken the morale of the thieves.
Just answering from common sense.
Perhaps, paramilitary men in the house can give us professional advice.

Police officers use their sirens for a variety of reasons when responding to emergencies or pursuing suspects. When going to arrest a criminal or thief, the police might use their sirens to alert the suspect that they are being pursued and to create a sense of urgency.

As an emergency, the loud, attention-grabbing sound of the siren can also help to clear the way for the police vehicle, allowing them to move more quickly and safely through traffic reducing carnages.

That is, the siren can be used to alert pedestrians and other drivers to the presence of the police vehicle, reducing the risk of accidents.

Also it's psychological in some cases, the use of a siren might also be intended to intimidate or discourage the suspect from fleeing or engaging in further criminal activity. The loud, piercing sound of the siren can create a sense of fear or anxiety in some individuals, making them more likely to comply with police instructions and surrender peacefully. The victims of these crimes are also reassured that help is near.

Overall, the use of sirens by police officers is intended to help them respond quickly and safely to emergencies, while also alerting the public to their presence and deterring criminal activity.

For Nigerian Police, the siren is to make the criminals leave/escape so there'll be no confrontation. In the western world and some others sirens are only used to stop traffic law violators i.e. overspeeding and red light infractions. They rarely use siren when approaching serious crime scenes in order not to alert the criminals to their presence or approach

youngrichnigga:
For Nigerian Police, the siren is to make the criminals leave/escape so there'll be no confrontation. In the western world and some others sirens are only used to stop traffic law violators i.e. overspeeding and red light infractions. They rarely use siren when approaching serious crime scenes in order not to alert the criminals to their presence or approach

CAP !!

This makes me realize I need to buy a siren for personal use. Once you call the police, them no dey gree come on time especially during a home invasion. Na to blast siren so thieves go pick race long before the police give themselves sense.

Same globally. To alert n commute freely while trailing where emergency, emerged from.

ThinkSmarter:
Just like an ambulance on an emergency.
they do so to alert road users to pave way for traffick, create tension to psychologically weaken the morale of the thieves.
Just answering from common sense.
Perhaps, paramilitary men in the house can give us professional advice.

police dey blow siren for midnight too even there is a robbery case..

Reminds me of the purge siren, very dreadful sound.

To distract the thieves and confuse them.