* Claudius, the King: This is his primary suspect. Hamlet has strong evidence, including the ghost's testimony and Claudius's suspicious behavior (e.g., marrying his brother's widow quickly).
* Polonius, the Lord Chamberlain: Initially, Hamlet suspects Polonius of being involved in the murder. This is based on his suspicion that Polonius is spying on him and his desire to manipulate him.
* The Queen, Gertrude: While Hamlet doesn't explicitly accuse her of murder, he blames her for marrying Claudius so quickly after his father's death, viewing it as a betrayal. He also believes she is complicit in Claudius's actions.
However, Hamlet's primary focus throughout the play is on Claudius. He is consumed by the need to prove Claudius's guilt and exact revenge. His suspicion of Polonius and his complex feelings towards his mother are ultimately secondary to his obsession with Claudius.