The murder used a .38 caliber revolver, according to a forensic scientist in Day 14 of the La Mesa Street Murders trial.
A forensic scientist told the jury on Monday their analysis of the recovered bullets and fragments concluded the murderer used a .38 caliber revolver to shoot 35-year-old Luis Rios and 6-year-old Danny Heredia, III.
"I would expect a .38 special type or .357 Magnum," Department of Public Safety Firearms Specialist Lisa Peloza told the jury, "More than likely, I would expect to see a revolver however, my mind would be open to something I have never seen."
The prosecution showed the jury several pictures of four recovered bullets and bullet fragments. Peloza said the fragments belonged to one of the bullets.
While Peloza confirmed the bullets were fired from the same weapon, scientists were never able to confirm a match to the handguns submitted for analysis.
"I was able to determine that the bullets I received were fired from the same firearm," Peloza explained.
Peloza said she analyzed several weapons and all, but two, were ruled out. Results for two firearms were inconclusive.
"When I needed to make the determination that the bullets were fired from the firearm, I looked at the reproduction of markings. However, sometimes there weren't enough differences to say they were not fired from a firearm," Peloza explained about the two guns with inconclusive results.
According to Peloza, one of the bullets was also missing several fragments beyond the cannelure ridge.
Concerns were raised by the defense over its difference in appearance but Peloza explained it was still the same type of bullet only it was missing some fragments, that look like petals after the bullet is fired, which caused it to look different.
"Could it be possible the fragments were lost?" prosecutor Karolyn Kaczorowski later asked.
"Yes," Peloza answered.
"Could it be possible they got lost going in a skull, through a skull, and out into the ground by the pool?", Kaczorowski probed.
"Yes," Peloza replied.
On Monday, the jury also heard from Yuma Police Department Crime Analyst Renae Sizemore.
In January of 2012, Sizemore was tasked with investigating Preston Strong's bank statements from January of 2004 through January of 2006.
Sizemore said that several transactions were handled between a woman named Adriana Osuna and Preston Strong.
Sizemore told the jury that Osuna's bank records were also investigated.
"Her spending habits were typical of someone supporting a household," Sizemore explained.
However, Strong's bank account statements showed that he rarely made regular payments such as those associated with, "a mortgage, rent, utilities, cable, phone or car payments," Sizemore explained.
From January of 2004 through July of 2004, Strong had a steady income coming from a source called the "travelers" which deposited $1290.80 every two weeks.
Strong, also seemed to spend his money as quickly as he got it, Sizemore explained, often incurring overdraft fees.
However, Sizemore said Strong's income stopped from August of 2004 through April of 2005 and his transactions also changed reflecting deposits from other sources.
Strong's bank account activity also showed he cashed checks at Sunshine Market, Quality Market and RC liquor.
According to the prosecution all three businesses are liquor stores. Quality Market and RC Liquor are both owned by Ray Shaya.
"The first check Strong attempted cashing at RC Liquor was in April of 2005 for $600 and it bounced," Sizemore explained.
"When no travelers checks were coming in, it seems he got more checks from others," Sizemore explained, "Cash deposits also seemed to increase and were more sporadic."
The "travelers" resumed the $1290.80 deposits in May of 2005. In January of 2006, Strong received an $80,000 deposit. A few days after, Strong made a withdrawal for $19,500.00.
(During opening statements the Defense argued that sometime after the murders Strong paid Luis Rios' brother back about $19,000 that he owed him. However, there was no connection made to the January 2006 withdrawal during Monday's proceedings.)
Moreover, the prosecution didn't provide further explanation of the "Travelers" identity or relationship to Strong.