Story highlights Gun-related murders in Connecticut drop an estimated 40% since law requiring background checks and gun safety training

Another recent study finds that gun-related homicide rose by 23% after Missouri repealed its decades-old gun law in 2007

(CNN) The rate of gun-related murders fell sharply in the 10 years after Connecticut implemented a law requiring people buying firearms to have a license, according to a study.

In 1995, a permit-to-purchase handgun law went into effect in Connecticut, stating that people who want to buy a gun must apply for a license (or permit) with the local police, a process that involves a background check, as well as complete at least eight hours of gun safety training. The law also raised the minimum purchasing age from 18 to 21.

To assess the effect of this law, researchers identified states that had levels of gun-related homicide similar to Connecticut before 1995. These include Rhode Island, New Hampshire and Maryland. When the researchers compared these states to Connecticut between 1995 and 2005, they found the level of gun-related homicide in Connecticut dropped below that of comparable states.

Based on the rates in these comparable states, the researchers estimated Connecticut would have had 740 gun murders if the law had not been enacted. Instead, the state had 444, representing a 40% decrease.

"I did expect a reduction [but] 40% is probably a little higher than I would have guessed," said Daniel Webster, director of the Johns Hopkins Center for Gun Policy and Research who led the study, which was published Friday in the American Journal of Public Health.

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