"Apparently tipped off" is the Dangling modifier.
Logically it should modify the suspect not the police. And the suspect should touch the modifier.

Thus A and B are discarded.

C and D are not correct logically.

Only E is valid

Apparently tipped off, the police were not able to capture the suspect, who was fleeing the house before they arrived.

In this kind of question -

ASK this question

Who was apparently tipped off ?
primarily there are 2 nouns in this sentence ---

the police, or the suspect

Remember its possible that police might have been tipped off - but that's not the case here.

A. the police were not able to capture the suspect, who was fleeing the house before they arrived
Option A wrongly modifies the noun police - which is not the correct recipient of the opening modifier, "Apparently tipped off ".

who was fleeing the house ( fleeing is a present participle - which is improperly used here)
before they arrived ( They - police is singular common noun , they doesn't have any antecedent )

B. the police, have not been able to capture the suspect, who fled as they arrived
Option B wrongly modifies the noun police - which is not the correct recipient of the opening modifier "Apparently tipped off ".

who fled as they arrived - ( They - police is singular common noun , they doesn't have any antecedent )

C. the suspect fled the police, who are not able to capture him at the house

the suspect fled the police - the suspect fled the house, and not the police

Couple of references from Merriam dictionary :

1. The family fled from Nazi Germany to Britain in 1936.
2. He was accused of trying to flee the scene of the accident.
3. Many people fled the city to escape the fighting.
4. He was forced to flee the country.


D. the suspect arrived before the police were fleeing the house

This really changes the meaning - whereby suggesting that

The Police were trying to escape, and the suspect arrived before that.

E. the suspect fled the house before the police arrived

This is the correct answer.

E is the right answer. Good explanations all