## Core Concept
The scenario involves a criminal investigation where a person has allegedly broken someone's mandible (jawbone) in a fight. The police have the authority to investigate and take actions under various legal provisions. The key concept here revolves around the legal powers granted to the police in cases of assault or causing harm.

## Why the Correct Answer is Right
The correct answer, , implies that the police can arrest the accused without a warrant under Section 151 of the Code of Criminal Procedure (CrPC) for a cognizable offense. Breaking someone's mandible can be considered a serious injury, potentially falling under offenses related to causing grievous hurt (Section 325 IPC) or even attempted murder (Section 307 IPC), depending on the intent and severity. These are cognizable offenses, allowing police to make an arrest without a warrant.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is incorrect because it does not accurately reflect the police's power in such scenarios.
- **Option B:** This option might suggest a need for a warrant, which is not required for cognizable offenses.
- **Option C:** If this option suggests a more limited action than arresting the accused, it would be incorrect given the severity of the injury.

## Clinical Pearl / High-Yield Fact
In cases of alleged assault leading to serious injuries like a broken mandible, it's crucial to document the injury thoroughly, as this can serve as critical evidence. The police have the authority to investigate such incidents under the relevant sections of the Indian Penal Code (IPC) and the Code of Criminal Procedure (CrPC).

## Correct Answer Line
**Correct Answer: D. Arrest without warrant.**