I am a law school graduate. What I offer is mere information, not to be construed as forming an attorney client relationship.
Well, the police have a reasonable time period with which to charge you for a felony like armed robbery. So.....unlike a civil trial, that definite of time like 1 year doesn't exist for a STATUTE OF LIMITATIONS.
It also depends on if you are talking about an arrest warrant or the speedy trial right via the 6th amendment.
In Massachusetts,here is the code defining armed robbery:
GENERAL LAWS OF MASSACHUSETTS
PART IV.
CRIMES, PUNISHMENTS AND PROCEEDINGS IN CRIMINAL CASES.
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TITLE I.
CRIMES AND PUNISHMENTS.
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CHAPTER 265. CRIMES AGAINST THE PERSON.
Chapter 265: Section 17. Armed robbery; punishment.
Section 17. Whoever, being armed with a dangerous weapon, assaults another and robs, steals or takes from his person money or other property which may be the subject of larceny shall be punished by imprisonment in the state prison for life or for any term of years; provided, however, that any person who commits any offence described herein while masked or disguised or while having his features artificially distorted shall, for the first offence be sentenced to imprisonment for not less than five years and for any subsequent offence for not less than ten years. Whoever commits any offense described herein while armed with a firearm, shotgun, rifle, machine gun or assault weapon shall be punished by imprisonment in the state prison for not less than five years. Any person who commits a subsequent offense while armed with a firearm, shotgun, rifle, machine gun or assault weapon shall be punished by imprisonment in the state prison for not less than 15 years.
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BUt to look up and find that info: try this link and try the procedure sections
http://www.state.ma.us/legis/laws/mgl/gl-pt4-toc.htm