He had a perfect alibi and the police let him go.alibial‧i‧bi /ˈæləbaɪ/ ●○○ noun [countable] 
He had a perfect alibi and the police let him go.2an excuse for something you have failed to do or have done wrong
WORD ORIGINalibi
Origin:
1600-1700 Latin ‘somewhere else’EXAMPLES FROM THE CORPUS
- According to Ken Harris, she has a cast-iron alibi.
- An excellent alibi, too: no one would question the word of the esteemed Professor Summerlee.
- And it was my lies to the police which had given him his non-existent alibi.
- But he also walked through the 17-year history of his relationship with Nicole and every last detail of his alibi.
- But it gives Tom an unimpeachable alibi.
- Nor did he review his alibi in any detail.
- When an alibi was produced, they said the offence took place in May 1992.
COLLOCATIONS FROM THE ENTRY He had a perfect alibi and the police let him go.COLLOCATIONS FROM THE CORPUSVERB
He had a perfect alibi and the police let him go.· And it was my lies to the police which had given him his non-existent alibi.· But it gives Tom an unimpeachable alibi.
PHRASES FROM OTHER ENTRIES
1something that proves that someone was not where a crime happened and therefore could not have done ita perfect/cast-iron/unshakeable etc alibi- According to Ken Harris, she has a cast-iron alibi.
- Do not expect a cast-iron guarantee of success.
He had a perfect alibi and the police let him go.2an excuse for something you have failed to do or have done wrong