Customs and Border Protection’s acquisition and installation of new border wall segments along portions of the southern U.S. border is lacking in terms of required analysis and planning to achieve operational control of the border, the Department of Homeland Security’s Inspector General charges in a new report.

CBP failed to conduct an updated analysis of alternatives required as part one of the required milestones for any major DHS acquisition project, didn’t properly prioritize where different sections of border barriers should be built first, and still doesn’t have an implementation plan to accompany its strategy for obtaining and maintaining operational control of the southern border, Joseph Cuffari wrote in a July 14 report that was released on Thursday.

In his conclusion to the 40-page report, Cuffari said, “CBP has not fully demonstrated that it possesses the capability to potentially spend billions of dollars to execute a large-scale acquisition to secure the southern border.”

Prior to President Trump taking office in January 2017, CBP had deployed 654 miles of various pedestrian and vehicle fencing along stretches of the southern border. Under Trump, the administration has reprogrammed, transferred and Congress has appropriated about $15 billion in funding for a new steel bollard barrier that so far is largely going toward replacing existing fencing.

As of July 10, CBP said it has about 201 miles of new primary and an additional 34 miles of new secondary wall system constructed since January 2017.

In his report, Cuffari pointed out that as a major DHS acquisition program the border wall system must go through a series of acquisition decision events leading to deployment and life-cycle management. The second event, the analyze and select phase, requires an Analysis of Alternatives (AoA) to select the most cost effective and appropriate solution.

In executing the acquisition of the new wall system, CBP relied on AoA results completed in 2008 that “did not reference the locations prioritized by Border Patrol for border wall investment” and relied on old cost estimates–$8 million per mile—versus newer estimates–$25 million per mile, Cuffari said.

“Without full and up-to-date AoAs, CBP cannot accurately identify the cost, effectiveness, and risk of potential material alternatives to meet its mission requirement,” he said.

The report also said that CBP ignored its own decision support tool in prioritizing where to build segments of the wall. Cuffari said a CBP board “adjusted the rankings without documenting its rationale for prioritizing certain lower scoring southern border locations over those that the decision support tool had scored higher for investment in impedance and denial.”

Finally, Cuffari said that DHS hasn’t done the planning needed to achieve control of the southern border.

DHS, belatedly, produced a strategy for securing the border but never developed an implementation plan, he said.

“Without an implementation plan, the Department cannot ensure it will fulfill its mission requirements with effective, appropriate, and affordable solutions,” Cuffari said.

Cuffari recommends and up-to-date AoA, a revised methodology for prioritizing investments on the southern border, and that DHS determine a need for an implementation plan to carry out its border security strategy.

DHS said it agrees with the second recommendation but not the first and third ones. DHS said it analyzed alternatives in its Border Security Improvement Plan (BSIP) and that a 2018 Executive Order Implementation Plan (IPLAN) combined with the provides the necessary implementation guidance.

Cuffari said neither plan is a substitute for an implementation plan.