Police officers are generally free to determine when to arrest someone; they need freedom to investigate the crime and collect evidence.
In general, an arrest made before the statute of limitations for the crime in question has expired is considered timely. (Some crimes, such as murder, have no statute of limitations.) On the other hand, sometimes a law enforcement delay in arresting a suspect isn't justifiable and compromises the suspect's ability to defend against the eventual charges. In that instance, a court might dismiss the case.
When a delayed arrest jeopardizes a defendant's right to a fair trial, due process requires dismissal of the charges. For that to happen, a defendant must show that the delay unfairly harmed his or her defense. It's not enough to simply claim that the erosion of time caused the loss of evidence (for example, documents or witnesses' memories). Rather, the defendant must detail the specific ways in which the delay compromised his or her defense.
Example: A defendant's claim that a delayed arrest prevented him from finding former coworkers to testify on his behalf was insufficient to establish prejudice. The defendant didn't give any details as to how the unnamed witnesses could have supported his defense. (People v. Patton, 775 NW2d 610 (Mich. 2009).)
To overturn a conviction, many courts also require that a defendant show that officers intentionally delayed the arrest in order to benefit the prosecution's case. An example would be deliberately postponing an arrest until evidence favorable to the defendant is no longer available.
Example: The police arrested the defendant 19 years after the homicide in question. They failed to verify a statement the defendant gave a few days after the murder and didn't compare available DNA samples. But the defendant failed to show that the prosecution intentionally delayed the arrest in order to gain a strategic advantage over the defense. Accordingly, the delay didn't violate his due process rights. (Morrisette v. Commonwealth, 569 S.E.2d 47 (Va. 2002).)
Some courts don't require that the defendant show that the government caused the delay to purposefully harm the defense. Instead, after a defendant establishes that the delay compromised her case, the prosecution must show a legitimate excuse for the delay. The court then considers both the extent of the prejudice and the reason for the delay to determine if there has been a violation of due process rights.
Example: A trial court properly found that a pre-arrest delay of approximately three years, half of which was due to government negligence, violated the defendant's due process rights. (State v. Hope, 89 So.3d 1132 (Fla. 1st DCA 2012).).
If you have been arrested, immediately contact an experienced criminal defense attorney to discuss the circumstances surrounding your case. A knowledgeable attorney will be able to advise you of the applicable law and offer you critical advice.