the Chronicle commissioned a new headquarters at 901 Mission Street on the corner of 5th Street in what is now the South of Market (SoMa) neighborhood of San Francisco. It was designed by Charles Peter Weeks and William Peyton Day in the Gothic Revival architecture style, but most of the Gothic Revival detailing was removed in 1968 when the building was re-clad with stucco. This building remains the Chronicles headquarters in 2017, although other concerns are located there as well. Between World War II and 1971, new editor Scott Newhall took a bold and somewhat provocative approach to news presentation. Newhall's Chronicle included investigative reporting by such journalists as Pierre Salinger, who later played a prominent role in national politics, and Paul Avery, the staffer who pursued the trail of the self-named "Zodiac Killer", who sent a cryptogram in three sections in letters to the Chronicle and two other papers during his murder spree in the late 1960s. It also featured such colorful columnists as Pauline Phillips, who wrote under the name "Dear Abby," "Count Marco" (Marc Spinelli), Stanton Delaplane, Terence O'Flaherty, Lucius Beebe, Art Hoppe, Charles McCabe, and Herb Caen. The newspaper grew in circulation to become the city's largest, overtaking the rival San Francisco Examiner. The demise of other San Francisco dailies through the late 1950s and early 1960s left the Examiner and the Chronicle to battle for circulation and readership superiority. Joint operating agreement The competition between the Chronicle and Examiner took a financial toll on both papers until the summer of 1965, when a merger of sorts created a Joint Operating Agreement under which the Chronicle became the city's sole morning daily while the Examiner changed to afternoon publication (which ultimately led to a declining readership). The newspapers were officially owned by the San Francisco Newspaper Agency, which managed sales and distribution for both newspapers and was charged with ensuring that one newspaper's circulation did not grow at the expense of the other. Revenue was split equally, which led to a situation widely understood to benefit the Examiner, since the Chronicle, which had a circulation four times larger than its rival, subsidized the afternoon newspaper. The two newspapers produced a joint Sunday edition, with the Examiner publishing the news sections and the Sunday magazine, and the Chronicle responsible for the tabloid-sized entertainment section and the book review. From 1965 on the two papers shared a single