Shares of Taser International, the US company that makes stun guns, have dropped 4.4% after US regulators stepped up an inquiry into the firm.
Life saver or death risk?
Taser has been criticised over the safety of its weapons and is facing a range of lawsuits from shareholders and families of Taser victims.
The company's stock has lost more than 80% of its value so far this year.
The Securities and Exchange Commission (SEC) has now expanded its inquiry, allowing it to seize documents.
The SEC had already opened an informal investigation into the company over the safety of its stun guns and the accounting for a distribution deal struck late in December 2004.
Taser's stun guns are designed to disable victims with a 50,000-volt shock.
The company has faced several wrongful death lawsuits from families of victims this year. However, none of these suits has yet been successful.
Human rights campaigner Amnesty International says it has registered more than 100 Taser-related deaths since 2001.
Taser claims its weapons are "non-lethal" and, in fact, save lives when used by police officers instead of traditional hand guns or rifles.
Chief executive of Taser, Rick Smith said he hoped the SEC's probe would address "all pertinent issues".
In September 2003, Taser's stock began to take off as more and more US law enforcement agencies used the stun guns, taking its stock to an all-time high of $33.45 a share late last year.
Now its share price stands at just over $6.