Japanese by Example
Learning through examples in manga

Don't suspect only me with 〜だけ

名探偵コナン » Volume 11 » Page 10

In a snow-covered mountain villa, a room full of suspects listens as Detective Mouri explains how their host was murdered. The accused notes she has a receipt showing she was at the convenience store at the bottom of the mountain when the murder took place.

"Moreover, Mr. Kanazawa's alibi is also vague!"
"Don't treat only me as the suspect!"

だけ limits the object being treated as a suspect to 「(わたし)」.