Bryce McIntosh was charged on Thursday with his son's murder as the search continued for the boy's body.
According to a court document, investigators believe Bryce McIntosh purchased acid, bolt cutters, a 32-gallon trash can and other items before the boy went missing.
Evidence collected by detectives prompted searches at locations throughout Riverside County including Temescal Valley, Aguanga and Murrieta.
Detectives said evidence collected at those sites were enough to add murder and a special circumstance charge of torture murder to the accusations stacked against McIntosh.
MORE: Murder charge filed against father of missing Corona boy
The court document sheds light on some of that evidence, which includes data from McIntosh's cellphone, computers and other electronic devices and storage devices.
On March 4, detectives said McIntosh went to a Home Dept store and purchased two pairs of long cuffed gloves, 24-inch bolt cutters, four gallons of muriatic acid, and one 128-ounce bottle of drain opener.
Data extracted from McIntosh's cellphone showed numerous searches conducted on March 4 for "normal heart rate for 8 year old" and "normal heart rate for 8 year old when they are running" and "how exactly sodium hydroxide works" and "sodium hydroxide to water."
During searches of McIntosh's laptop and desktop computers, an FBI agent located web searches dated March 4 and March 5. The web searches included, "What exactly is sulfuric acid," "What does Sulfuric acid do to aluminum," "Can you buy sulfuric acid," "What kind of plastic can stand uriatic [sic] acid," "clean shot drain opener sulfuric asid [sic] MSDS."
Cellphone data also showed locations where McIntosh's phone was at different times on March 4 and March 5.
MORE: Investigators, plumber spotted at boy's home amid ongoing search for missing Corona boy
On March 5, his cellular phone was in the area of Wilson Valley Road, north of Highway 371, in the unincorporated area of Aguanga, the document states. FBI agents and Corona police officers found a trash can, a paper with "Noah M" written on it, purple latex gloves, a plastic bag with residue consistent with blood, parts to a Ninja blender, empty bottles of drain cleaner, empty cans of oven cleaner, blankets, yellow towels and one blue long cuffed glove.
During a search of McIntosh's home, authorities found an owner's manual for a Ninja blender, but no Ninja blender was located inside the residence, the document stated.
According to the document, many of the items located matched items that were either located at McIntosh's residence, in his car, or that he was seen purchasing.
Also on March 4, McIntosh went to a Lowe's Home Improvement store in Corona and purchased a 32-gallon Brute trash can and a 32-ounce bottle of sulfuric acid drain opener, the document states, adding that McIntosh also went to a Target and bought two bottles of drain opener.
The trash can he purchased matched the one located by police on March 16 at a site off Wilson Valley Road, the document states.
On the evening of March 18, a investigators were seen taking a plumber into McIntosh's home. The court document explained police hired a plumbing company to assist them in conducting a search warrant at the residence. That plumber removed the P traps from the home's bath tubs, bathroom sinks and kitchen sink. The plumber told investigators that the P trap for the tubs appeared cleaner than a normal P trap considering the age of the building.
The document also includes information pulled from the cellphone of Noah's mother, Jillian Godfrey, who was also taken into custody on charges of willful child cruelty. This evidence included notes taken by Godfrey documenting McIntosh allegedly abusing Noah.
Examples included McIntosh admitting to putting Noah in hot water, Noah being placed in cold water for approximately 2 1/2 hours, Noah being put in a tub of cold water for over six hours, and evidence of Noah being in Bryce's bathroom with his feet tied up.
Investigators also said they interviewed McIntosh's young daughter, who described physical abuse to Noah "by her daddy." The abuse involved being in the bathtub, cold water and Noah being handcuffed, the document stated. She described helping her dad hold Noah's legs down in the water.
The investigation began March 12 when Godfrey called police and requested a welfare check of Noah at his father's home in 4600 block of Temescal Canyon Road. At the time, the mother said she had not been able to contact Noah for almost two weeks.
According to the Police Department, officers attempted to contact Bryce McIntosh at the residence but he did not answer. They returned to the apartment the following day with a search warrant and subsequently arrested both parents for child abuse.
Anyone with information about the case, or who may have seen McIntosh's black BMW 330i, with California license No. 5MKE807, is asked to contact police Senior Detective Mario Hernandez by phone at (951) 279-3659 or email at Mario.Hernandez@CoronaCA.gov.