However, upon arriving in New York, they learned the two-year-old child had died of diphtheria. They again returned to Greytown, and there Hollenbeck rebuilt his general merchandise business. He also began diversifying, buying a river steamer from the now struggling Transit Company. In the fall of 1860 Hollenbeck considered returning to the United States, and briefly established a home in Missouri. He continued to travel to Central America to manage his businesses. However, the impending conflict of the American Civil War caused great economic concern. With the outbreak of war, an embargo was laid on travel and business; railroads were torn up and soldiers quartered in every town. So, he and his wife returned yet again to Greytown in 1865. Shortly after his return, he obtained commissions as agent for the Royal Mail ships and agent for an English mining company, shipping large quantities of India rubber, Brazil wood, hides, cedar, rosewood, coffee, indigo, and other products. On June 6, 1867, he and his wife arrived in New York City from Greytown, continuing to Hamburg, Germany, from where they returned to New York City on Sept. 28, 1867. After returning to Central America, the Hollenbecks were back in New York City on October 6, 1869. About 1872, the Transit Company closed all its Nicaraguan operations and Hollenbeck, with three partners, bought all the American company’s property and assets. In 1874, a wealthy man but experiencing health difficulties, Hollenbeck and his wife visited Los Angeles, California. The community was growing rapidly, and businesses were investing heavily in anticipation of the coming of the Southern Pacific Railroad. While visiting California, Hollenbeck purchased several parcels of real estate and deposited funds in Temple and Workman Bank. Hollenbeck soon closed out his Nicaraguan businesses and made his final move to the United States. Prior to his leaving Nicaragua, the Government appointed him Minister Plenipotentiary to the United States, and on his return he visited Washington, D.C., transacting business for the Nicaraguan government in this capacity. Arriving in Los Angeles early in the spring of 1876, Hollenbeck purchased land on the east side of the Los Angeles River, and built a large residence with broad verandas and a tower on extensive grounds on Boyle Avenue. He made twenty-seven acquisitions of property by 1880; spending $108,875 for a total of . The real estate holdings included south of the city limits, much of which was planted in vineyards.