More homemade explosives and bomb-making materials were found Wednesday by bomb and explosives experts during a search of a Escondido home rented by man arrested a week ago when an explosion injured his gardener and prompted the partial closing of Interstate 15.According to San Diego County sheriff's officials, among the items found were a half-jar of the chemical hexamethylene triperoxide diamine (HMTD), pentaerythritol tetranitrate (PETN), grenades and weapons. Investigators also seized computers that will be analyzed.Most of the explosives were left in the house, because they are too dangerous to remove, according to sheriff's deputies, who are working on a plan to dispose of the chemicals. The HMTD and PETN found in the home has been stabilized, authorities said.Experts said PETN is the explosive compound that the Transportation Security Administration is hoping to detect though the use of full body scans at airports.According to explosives experts, PETN -- which was molded into the sole of Richard Reid's shoe and in the so-called underwear bomber's underclothing when he was caught on Christmas Day 2009 -- has been considered a favorite of terror group al-Qaida. The sand-like compound is hard to sniff out and does not set off metal detectors, experts said."This is a very cluttered environment. There were items that were just stacked on every open spot, desktops, tabletops, countertops. There's no spaces that are not full of clutter," Asst. Sheriff Prendergast said.The messy conditions made a tough job even more difficult for bomb technicians to move around inside the house."You had our bomb techs wearing their protective gear which reduces their mobility," Prendergast explained. "So all it would take is them knocking over the wrong thing and it could cause a potential explosion."Prendergast also said investigators found evidence consistent with robberies, although they could not elaborate specifically on what was found."I'm not saying there was a ski mask in there, but you get the idea, disguises," said the Prendergast. "I've been doing this for 29 years. This is certainly the most complex problem I've ever encountered."The streets leading to alleged bomb maker George Jakubec's home in the 1900 block of Via Scott were shut down once again. Only residents who live on the street were able to enter the area, and those who live in the two residences closest to Jakubec's home are still evacuated.Jakubec, 54, was arrested last week when the explosion occurred in the back yard of home.Jakubec's gardener, Mario Garcia, 49, of Fallbrook, suffered injuries to his left eye and left arm after stepping on something akin to a mine.Hazmat crews hauled away the following bomb-making materials: 50 pounds of hexamine, 4 liters of hydrochloric acid, 1 liter of nitric acid and 25 gallons of sulfuric acid. Those ingredients aren't so harmful by themselves, but when combined experts say they are an explosive brew.Authorities have called off the search of the house for the long holiday weekend. They plan to meet Monday to determine the next step.Jakubec, described as a computer software consultant, is facing explosive charges and jailed in lieu of $5 million bail.