[Updated at 11:58 a.m. ET]
O'Mara asks if Zimmerman's gun is a safe one to carry loaded. "This gun, again in working order, is safe in terms of it will not fire unless the trigger is pulled," says Siewert. She says having a loaded gun be considered safe is a personal preference.
[Updated at 11:57 a.m. ET]
Siewert says the trigger on this gun in particular needs to be pulled back much farther than other guns. She says this feature potentially makes it safer.
[Updated at 11:56 a.m. ET]
O'Mara says that if someone were carrying a gun for self-defense, they would want it ready to fire and to not have a safety. Siewert says she believes that's personal preference.
[Updated at 11:53 a.m. ET]
Defense attorney O'Mara has Siewert hold Zimmerman's gun. She says that the "double action" aspect of the gun also works as a safety feature. She agrees that a double-action gun, when it's ready to fire, is safer to carry than a single-action gun that's ready to fire.
[Updated at 11:48 a.m. ET]
Siewert did the same test on Martin's inner shirt.
"This as well was consistent with residues and physical effects consistent with a contact shot," said Siewert. She says she believes the muzzle of the gun was against Martin's sweatshirt when it fired. The prosecution has finished its questions.
[Updated at 11:47 a.m. ET]
Zimmerman's gun and one of the live rounds was used by Siewert to conduct a test on part of the fabric from Martin's hooded sweatshirt.
"The clothing displayed residues and physical effects consistent with a contact shot," says Siewert.
[Updated at 11:44 a.m. ET]
Siewert looks at a close-up of the sweatshirt where the bullet entered. She says there was darkening, tearing of the fabric, burning and singing.
[Updated at 11:42 a.m. ET]
Siewert also examined the shirt Martin was wearing under his black hoodie. She also removed part of this shirt for testing.
[Updated at 11:40 a.m. ET]
Prosecutor John Gun brings out Martin's black sweatshirt. Siewert explains how she examined the area around the gunshot. She says she removed a portion of the back of the sweatshirt for testing purposes.
[Updated at 11:37 a.m. ET]
Siewert couldn't tell if bullet fragments were fired from the gun because they were damaged.
[Updated at 11:35 a.m. ET]
The trigger pull for the gun was measured between 4½ and 4¾ pounds, according to Siewert. She also matched the shell casing found at the scene with Zimmerman's gun.
[Updated at 11:32 a.m. ET]
Siewert shows jurors how the gun works. She says the gun's magazine was fully loaded and one cartridge was in the chamber at the time the gun was fired. She also says there are safeties in place to keep the gun from accidentally firing.
[Updated at 11:27 a.m. ET]
Siewert examined Zimmerman's gun and says a pull of the trigger is required every time the gun is fired. She test-fired the gun and found that it was functional.
[Updated at 11:25 a.m. ET]
The prosecution has called Amy Siewert to the stand. She is a crime laboratory analyst with the Florida Depart of Law Enforcement and is reviewing her education and background.
[Updated at 11:22 a.m. ET]
In their introductions during the first week of class, Pleasants says, Zimmerman said he wanted to become an attorney and eventually a prosecutor. The witness is excused.
[Updated at 11:20 a.m. ET]
Pleasants says he didn't cover strategies as a witness or testifying in the class discussions, but it was part of the required reading.
[Updated at 11:18 a.m. ET]
There was no course work that touched on criminal profiling, according to Pleasants. He says there are records that Zimmerman participated in all the online discussions that they had. He's reviewing the records.
[Updated at 11:16 a.m. ET]
O'Mara is now asking Pleasants questions. The professor says his class was online and there was no required attendance. Pleasants says he can't guarantee that what's in the textbook was covered in class or that students in the class read the material.
[Updated at 11:12 a.m. ET]
Multiple people keep trying to call into the Skype conversation. O'Mara says he believes they're being toyed with, so they're now calling Pleasants back on the phone.